Research Classification
Research Interests
Relevant Thesis-Based Degree Programs
Affiliations to Research Centres, Institutes & Clusters
Research Options
Research Methodology
Recruitment
Complete these steps before you reach out to a faculty member!
Check requirements
- Familiarize yourself with program requirements. You want to learn as much as possible from the information available to you before you reach out to a faculty member. Be sure to visit the graduate degree program listing and program-specific websites.
- Check whether the program requires you to seek commitment from a supervisor prior to submitting an application. For some programs this is an essential step while others match successful applicants with faculty members within the first year of study. This is either indicated in the program profile under "Admission Information & Requirements" - "Prepare Application" - "Supervision" or on the program website.
Focus your search
- Identify specific faculty members who are conducting research in your specific area of interest.
- Establish that your research interests align with the faculty member’s research interests.
- Read up on the faculty members in the program and the research being conducted in the department.
- Familiarize yourself with their work, read their recent publications and past theses/dissertations that they supervised. Be certain that their research is indeed what you are hoping to study.
Make a good impression
- Compose an error-free and grammatically correct email addressed to your specifically targeted faculty member, and remember to use their correct titles.
- Do not send non-specific, mass emails to everyone in the department hoping for a match.
- Address the faculty members by name. Your contact should be genuine rather than generic.
- Include a brief outline of your academic background, why you are interested in working with the faculty member, and what experience you could bring to the department. The supervision enquiry form guides you with targeted questions. Ensure to craft compelling answers to these questions.
- Highlight your achievements and why you are a top student. Faculty members receive dozens of requests from prospective students and you may have less than 30 seconds to pique someone’s interest.
- Demonstrate that you are familiar with their research:
- Convey the specific ways you are a good fit for the program.
- Convey the specific ways the program/lab/faculty member is a good fit for the research you are interested in/already conducting.
- Be enthusiastic, but don’t overdo it.
Attend an information session
G+PS regularly provides virtual sessions that focus on admission requirements and procedures and tips how to improve your application.
ADVICE AND INSIGHTS FROM UBC FACULTY ON REACHING OUT TO SUPERVISORS
These videos contain some general advice from faculty across UBC on finding and reaching out to a potential thesis supervisor.
Graduate Student Supervision
Doctoral Student Supervision
Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.
A study of interfacial heat transfer in the permanent die low pressure and counter pressure casting processes (2022)
Counter pressure casting (CPC) process is a relatively new, emerging technology developed for producing load-bearing parts. It is believed that CPC produces parts with superior quality compared to those produced by the conventional low pressure die casting (LPDC) process since the die cavity is placed within a pressurized chamber (2-3 bar) in CPC. This feature is claimed to benefit the process with respect to both filling and solidification. However, few studies are available in the literature providing data to support this claim. Therefore, this research program is aimed to improve the fundamental understanding of the transport phenomena occurring in the CPC process with a focus on the heat transfer through the die/casting interface, using a combination of experimental and modelling techniques.A series of experiments were conducted on a commercial CPC machine to produce a custom-designed “H-shaped” aluminum casting. Three process conditions, where the chamber pressure was varied, were tested. Results showed that in-die temperatures at various locations, and the secondary dendrite arm space (SDAS) were not significantly affected by the chamber pressure in the range tested (1200-3000 mbar). However, die filling was delayed at a higher counter pressure, possibly due to the increased viscosity and density of the air in the die cavity.A thermal model and a coupled thermal-stress model of the CPC process have been implemented within the commercial finite element (FE) package ABAQUS™ to simulate the process conditions in the experiments. The coupled thermal-stress model was developed using a novel modelling methodology established in the research. The model is able to utilize the deformed state of the hot die and update the casting geometry based on the hot die geometry at the beginning of a casting cycle. Thus, the stress-strain evolution of the die and the casting, the die/casting interface behaviour, and the associated heat transfer can be fundamentally described. A thermal-only model was also formulated and utilized to develop a second interfacial heat transfer coefficient that is a function of interface temperature. The results of the comparison indicated a slight improvement in accuracy obtained with the thermal-stress model in areas prone to gap formation.
View record
Dissolution of titanium-nitrogen inclusions in liquid titanium during electron beam melting (2022)
Ti-N inclusions, classified as Type I defects in titanium alloys, are nitrogen-enriched areas that locally embrittle and harden the material. The presence of Ti-N inclusions in titanium alloys significantly degrades the fatigue performance, and hence cannot be tolerated in rotor-grade applications. Both reducing the potential for the introduction of these inclusions and removing them in melt-refining processes are therefore critical. The research herein is aimed at understanding: (1) the diffusional transport of nitrogen in Ti and the associated solid-state phase evolution – sub-task 1, and (2) their subsequent dissolution of Ti containing ~ 2 wt. % nitrogen in liquid titanium – sub-task 2. In the first sub-task, nitrogen was introduced to solid commercially pure (CP) titanium rods at 1650 °C in an electric induction furnace. An effective way to avoid the formation of a nitride layer (TiN and Ti₂N) was developed. Microstructure and microhardness were examined on the cross-section of the nitrided samples. Multiple phase layers were observed, and each layer was identified using X-ray diffraction. The effects of temperature and nitriding time on the kinetics of nitrogen diffusion were investigated. Results showed that nitrogen diffusion was accelerated with increasing temperature and nitriding time. Correlations between microhardness and nitrogen concentration were developed for the core and outer layers, respectively. A numerical model has also been developed to simulate nitrogen diffusion. The predicted nitrogen concentration profiles and the displacement of the phase interfaces showed good agreement with experimental observations.In the second sub-task, the nitrided rods were immersed into a molten CP Titanium pool produced by an electron beam button furnace. The evolution of the rod profile over various time periods was observed. Generally, the volume fraction of dissolved Ti-N solid increases with increasing immersion time. A numerical model has also been developed to aid in understanding the transport phenomena involved in the dissolution process. Overall, the predicted dissolved volume fraction across different immersion times agrees well with experimental measurements. Finally, an effective mass transfer coefficient in the range of 4.2×10⁻⁵ to 4.9×10⁻⁵ m/s was derived based on model results, which can be used for evaluating the dissolution kinetics in industrial applications.
View record
Corrosion behavior of B206 aluminum-copper casting alloy in seawater environment: electrochemical and microstructural studies (2018)
Aluminum-copper casting alloys have relatively high strength and hardness, fatigue and creep resistances and good machinability, all of each are dependent on the copper content of the alloy. The Al-Cu casting alloy (4.2-5.0 wt% Cu), known as B206, is a potential candidate material for use in marine applications where good mechanical properties and high strength to weight ratio is desired. These properties are ideal for components of tidal-based energy generating systems. However, corrosion continues to be an issue. This dissertation presents and discusses the results of several electrochemical and microstructural investigations conducted on B206, contributing to a further understanding of the fundamental corrosion processes. Applications of this research are strongest within the marine industry field, yet are extendable to other infrastructural and engineering applications such as aerospace and military.Results of this work elucidate the mechanism of localized corrosion of B206 alloy in seawater. Focused ion beam (FIB) used to determine the subsurface microstructure at local attack sites within the corroded area reveals that localized corrosion is propagated where continuous particles are buried beneath the surface. Propagating away from the initiation sites, corrosion develops preferentially along the grain boundary network beneath the alloy surface. Retrogression and re-aging (RRA) of the alloy to modify the grain structure and render uniform the distribution of the second phase is revealed not to have a substantial effect on the corrosion susceptibility of the alloy. However, Electrochemical Impedance Spectroscopy (EIS) and Mott-Schottky tests support the feasibility of implementing anodizing and possibly anodic protection systems for B206 in specific service environments. EIS was also used to determine the effect of cathodic protection (CP) on coated B206 and reveals that its corrosion resistance with CP is superior to the situation without CP and, therefore, that the coating is compatible with CP. Due to its use in the as-cast state, the effect of casting porosity on the corrosion of B206 was investigated using a pencil electrode method. Results reveal that the corrosion can be attributed to the local chemistry inside the pores (conductivity and potential at the bottom of pores).
View record
Macrosegregation in solidification of A356 (2018)
A combined experimental / numerical approach has been applied to investigate thebulk transfer of solute due to liquid metal feeding during shape casting of aluminumalloy A356 (Al-7Si-0.3Mg). A series of dumbbell-shaped experimental casting geome-tries have been developed, which promote solute redistribution due to liquid metalfeeding. Three of the castings were produced in small moulds with natural cooling,forced cooling and insulated conditions and one casting was made in a large mouldwith natural cooling. The redistribution of solute in the castings has been evaluatedusing a novel image processing technique based on the area fraction of silicon. Theresults show that the casting with the forced cooling configuration exhibited a largerdegree of macrosegregation.In the numerical model, silicon segregation during solidification is calculated as-suming the Scheil approximation, and is coupled with a macro-scale transport modelthat considers resistance in the mushy zone and feeding flow. The model has beenimplemented within the commercial CFD software, FLUENT, which simultaneouslysolves the thermal, fluid flow fields and species segregation on the macro-scale. Theresults from the simulation agree with the experimental results, except for the caseswhere significant liquid encapsulation occurs. The model predicts high levels of enrich-ment when liquid encapsulation is present in the joint section of the dumbbell-shapedcastings.Finally, a constitutive behaviour relationship was developed based on the Ludwik-Hollomon equation to predict the flow stress of Al-Si-Mg alloys with varying siliconcomposition and Dendrite Arm Spacing (das) in the as-cast (ac) or T6 conditionwith high accuracy. This model was then used with the results of the segregationmodel to predict yield strength distribution in the aforementioned dumbbell-shapedcasting. The results show that silicon segregation has a more significant effect on the yield strength than das.
View record
Modeling of thermal stress cycling in refractory materials (2017)
In metallurgical reactors, the thermal stress field of refractories always changes with the heat transfer conditions at the hot-face. It is suggested that ‘thermally induced refractory cracking’ is often the primary cause of in-service refractory failure but quantitative support for this is lacking. The current work is focussed on studying this aspect by developing an experimentally validated thermomechanical model that considers refractory strength degradation under repeated thermal cycling.A thermo-mechanical model has been developed with ABAQUS to predict thermal stress and damage in a refractory specimen subjected to thermal cycling. An experiment based on the “contact-conduction method” that uses a hot/cold metal block to heat/cool a refractory specimen was carried out to validate the model. The experiments were run for up to 3-cycles starting from cold- and hot-refractory specimens. Thermocouples were used to gather temperature data from refractory and steel block. An inverse heat conduction model was developed to predict the heat flux applied to the refractory specimen by the steel block based on the temperature history from the steel block. Ultrasonic testing was carried out on the refractory specimens before and after the thermal cycling tests. The contact-conduction method was successful in creating significant thermal gradients in the refractory specimens. Thermocouples on refractory located at 1cm from the steel-refractory show temperature variation of about 500°C and 575°C for cold- and hot-refractory specimen, respectively after 3-cycles. The model was capable of predicting the temperature changes and damage in the refractory material after multiple cycles. Ultrasonic velocity tests show significant change in the sound velocities in the areas experiencing thermal cycling, indicating significant micro-cracking damage in those areas. It was seen that with multiple cycles the damage penetrated further into the specimen, however the magnitude of the damage does not increase significantly. Application to an example tundish operation indicated that the model was capable of analyzing an ideal preheating schedule and was capable of predicting the effect of idle time and multiple thermal cycles on the damage in refractories. However, to predict thermal spalling more precisely, an integrated model that considers the effect of thermal gradients, chemical reactions and mechanical loads is needed.
View record
Development of a Numerical Optimization Methodology for the Aluminum Alloy Wheel Casting Process (2016)
Aluminum alloy wheel manufacturers face on-going challenges to produce high quality wheels and increase production rates. Improvements are generally realized by modifying the wheel and die designs and continually improving the manufacturing processes. Conventionally, these improvements have been realized by trial-and-error, building on past practice or experience. This approach typically results in long design lead times, high scrap rates and less than optimal production rates. The work presented in this study seeks to reduce the reliance on trial-and-error techniques by developing a new methodology to optimize the wheel casting process through the combination of a casting process model and open-source numerical optimization algorithms. The casting process model utilized in this method was developed in the commercial finite element package Abaqus™ and was validated through plant trials. An open source optimization module Python Scipy.optimize has been employed to perform the optimization. The work focuses on optimizing the cooling conditions in a low-pressure die-casting (LPDC) process used to produce automotive wheels. Specifically cooling channel timing was selected because of the critical role heat extraction plays on casting quality, both in terms of dendrite cell size and the formation and growth of porosities. The methodology was first developed with a series of test problems ending with an L-shaped geometry that employed the major features of the wheel casting process. The most suitable approach, based on the test problems, was then applied to the optimization of a 2-D axisymmetric prototype wheel die structure. The outcome revealed that numerical optimization coupled with a state-of-the-art process model has the potential to dramatically improve the method of determining cooling channel timings while also improving the product quality and process performance. The utility of the optimization methodology was found to depend on the accuracy of the casting process model. Significant challenges remain before widespread implementation of this methodology can occur in industry. Possible directions for further developments have been identified. In summary, this study represents one of the initial applications of a numerical optimization methodology to wheel casting, and that with further development; it will become an effective tool for process and die design optimization.
View record
Melting of Solids in Liquid Titanium During Electron Beam Processing (2016)
Both experiments and numerical modeling work have been carried out to understand the phenomena contributing to the melting of solid condensate in liquid titanium alloys during Electron Beam Cold Hearth Re-melting (EBCHR). To begin, ice/water and ethanol/water analogue physical models were adopted to study the melting of a low melting point solid introduced into liquid and to provide data suitable for developing a comprehensive numerical-based modeling framework. The results revealed that thermal and compositional driven buoyancy and surface tension (Marangoni) flows, when present, can have a significant impact on solid melting in a system where forced convection is not significant. In work that followed, the melting behavior of Commercial Purity Titanium (CP-Ti) rods in liquid CP-Ti was investigated with the aid of an Electron Beam Button Furnace (EBBF) to examine the melting kinetics in the titanium system in the absence of compositional effects. The results showed that the liquid titanium initially froze onto the cold rod when it was immersed, resulting in the formation of a solid/solid interface that acted to retard melting when present. Data collected from the experiments included the evolution in the solid profile of the rod with time and the evolution in temperature obtained from a thermocouple embedded in the rod. The numerical modeling framework developed for the ethanol/water system was modified and applied to support analysis of the experimental results including the determination of an effective interfacial heat transfer coefficient (EIHTC). A similarity solution was also developed to assess the numerical model derived EIHTC. In the final phase of the study, work was conducted on Ti-Al solid rods partially immersed in liquid CP-Ti and liquid Ti-6wt%Al-4wt%V (Ti64) as a means of approximating the behavior of condensate in industry. The melting behavior of Ti-Al was observed to differ significantly from that of CP-Ti rods. Despite having a lower melting point, the Ti-Al rod was found to heat up and melt at a much slower rate. Metallographic examination of partially melted rods and a sensitivity analysis conducted with the numerical model has been able to partially, but not fully explain this difference.
View record
Rotary forming of cast aluminum (2013)
The application of rotary forming to A356 offers a potential improvement in material use, simplified castings and ameliorated fatigue resistance. To investigate the utility of adopting this process industrially, an extensive characterization and modelling effort was undertaken.The constitutive behaviour of A356 in the as-cast condition was assessed with compression tests performed over a range of deformation temperatures (30-500°C) and strain rates (~0.1-10/s). The flow stress as a function of temperature and strain rate was quantified via an extended Ludwik-Hollomon and Kocks-Mecking framework.The through-process microstructural effects on A356 subjected to rotary forming at elevated temperatures was also investigated. This was conducted on material at 350°C with an industrially-scaled, purpose-built apparatus, inducing varying levels of spinning deformation. This was also conducted on commercially flow formed material with high levels of deformation at the same temperature. Macro and micro-hardness testing was used to track the changes from the as-cast and as-formed states, as well as following a T6 heat treatment. Further EDX analysis indicate that precipitation aspects of heat treatment is not appreciably affected by forming. Forming was found to principally affect the eutectic-Si particle size, resulting in a finer particle post heat treatment.An explicit finite element rotary forming model reciprocating experimental forming conditions was developed incorporating the Ludwik-Hollomon description. This forming model was found to be computationally expensive; however, demonstrated reasonable agreement with experimental geometry and phenomena.In evaluating the effect of forming on fatigue, multiaxial testing of A356-T6 was conducted to apprehend the basic fatigue mechanisms. Endurance limits are found to be generally governed by porosity and maximum principal stress for high cycle fatigue. Uniaxial fatigue tests of both experimentally and commercially formed material showed a 30% increase in endurance limits over unformed material, principally through mitigating porosity.
View record
Defect minimizing control of low pressure die casting (2012)
Controlling and eliminating defects, such as macro-porosity, in die casting processes is an on-going challenge for manufacturers. Current strategies for eliminating macro-porosity focus on the execution of pre-set casting cycles, die structure design or the combination of both. To respond to process variability and mitigate its negative effects, advanced process control methodology has been developed to dynamically drive the process towards optimal dynamic or static operational conditions, hence minimizing macro-porosity in the casting.In this thesis, a Finite Element heat transfer model has been developed to predict the evolution of temperatures and the volume of encapsulated liquid in a casting with a high propensity to form macro-porosity. The model was validated by comparison to plant trial data. A virtual process has then been developed based on the model to simulate the continuous operation of a real process, for use as a platform to evaluate a controller’s performance.Since macro-porosity cannot be measured during casting, die temperature has been used as an indirect indicator of this defect. A model-based methodology has been developed to analyze the correlation between die temperature and encapsulated liquid volume, a precursor to the formation of macro-porosity. This methodology is employed to assess the suitability of different in-cycle die temperatures for use as indicators of macro-porosity formation. The optimal locations have then been determined to monitor die temperatures for the purpose of minimizing macro-porosity.A nonlinear state-space model, based on data from the virtual process, has been developed to provide a reliable representation of this virtual process. The control variable-driven portion exhibits linear dynamic behavior with nonlinear static gain. The resulting MIMO state-space model facilitated the design of a controller for this process.Finally, the performance of the nonlinear model-based predictive controller was evaluated using the virtual process. Independent of the initial state of the process - i.e. steady state or startup, the controller exhibited the capability to automatically adjust the process toward the dynamic or static optimal operational condition during disturbances examined. The advanced control methodology developed for LPDC provides a novel solution to improve the operational conditions in die casting process.
View record
Permeability of hypoeutectic aluminum alloys (2011)
The interdendritic permeability is a critical parameter that defines the feedability of the mushy zone during solidification. In this study, a theoretical expression to describe the evolution of permeability throughout the complete solidification range (from dendritic to dendritic/eutectic) of hypoeutectic aluminum alloys has been derived, verified and validated through physical and numerical modeling. The permeability of the primary, equiaxed, dendritic phase has been characterized using geometries obtained by X-ray microtomographic analysis of Al-4.5wt%Cu alloy samples quenched at different temperatures after the start of solidification. The permeability during equiaxed eutectic solidification was characterized on simulated dendritic/eutectic microstructures predicted using a Cellular Automaton technique. For both the dendritic and dendritic/eutectic structures, the permeability was characterized i) physically using large-scale analogues of the characterized microstructures and ii) numerically by predicting the flow through the simulated microstructures. The microstructural parameters were then linked to more practical parameters available in solidification models through i) developing an inverse analysis technique to characterize eutectic solidification and ii) development of a geometric model for dendritic solidification. The permeability values determined through physical and numerical modeling are in good agreement with each other and are consistent with the mathematical expression. The proposed permeability expression is valid over the complete solidification range and for a wide range of compositions. The expression reduces to the conventional Carman-Kozeny expression during dendritic solidification and/or dendritic/eutectic solidification with low density of eutectic grains. However, it deviates from the conventional Carman-Kozeny expression as the density of eutectic grains increases.
View record
Master's Student Supervision
Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.
Development of a heat transfer model of a simplified build environment in electron beam additive manufacturing (2022)
In this research, a 3D heat transfer model incorporating cavity radiation was developed in ABAQUS version 2017 to approximate the thermal field within the build environment in an Electron Beam Powder Bed Fusion (EB-PBF) Additive Manufacturing (AM) Process. The build environment, also referred to as the "pseudo build environment, was fabricated in an Electron Beam Button Furnace (EB BF) using an ARCAM Q20Plus heat shield (with the top section removed). The “build plate” was fabricated from a commercially pure titanium disk, which was surrounded by a stainless-steel plate. A circular beam pattern with a diameter of 50 mm was used to heat the titanium disk in the absence of powder. The experimental set-up was instrumented with type-K thermocouples to record the evolution in temperature on the heat shield walls, within the titanium disk and stainless-steel plate during the experiment. To record and store the temperature, an autonomous data acquisition system was developed for in-situ instrumentation within a vacuum environment. The model was validated with respect to the temperature data extracted from the EB BF.Overall, the results of the heating experiment and the numerical model suggest that the radiative heat exchange between various surfaces within the build environment is complex. The model results indicate that the portion of heat transferred via cavity radiation and absorbed by the heat shield walls was found to be a strong function of the titanium disk temperature. Additionally, four simple numerical case studies were developed to evaluate the effect of heating pattern, initial preheat, the heat absorption by the powder deposition sequence and post powder deposition preheat on the thermal behaviour in the pseudo build environment. The results of the numerical cases provide guidance into future model development, which can potentially aid in better understanding the heat transfer within the build environment leading to better AM process control.
View record
Mesoscale modeling of stress and strain evolution in electron beam powder bed fusion additive manufacturing (EB-PBF) (2022)
Components manufactured using the Electron Beam Powder Bed Fusion (EB-PBF) Additive Manufacturing method are often prone to deformation and residual stress caused by the repeated heating, melting, solidification, and cooling that occurs during the process. The presence of residual stress can reduce the service life of the parts. An estimation of the magnitude, state, and distribution of residual stress can aid in maintaining the dimensional accuracy of the component. Although effort has been made to understand the residual stress development in EB-PBF, understanding the complicated interaction between a newly deposited powder layer and the consolidated layer is still in its infancy. In this study, a coupled thermomechanical model was built to examine the buildup of stress and inelastic strain during the layer-by-layer processing of a part at the mesoscale level. A small mesoscale domain was developed to represent a volume extracted from within a much larger component. The sub-domain dimensions were chosen to include the total thickness of four powder layers and a section of previously deposited material equivalent to approximately eight consolidated layers. The model uses a novel approach to capture the transition in material response when the material changes from powder to liquid to solid. A user-defined subroutine was developed to correctly describe the evolution of thermal strain as the material solidifies and contracts. The mesoscale model developed in this work has been used to examine different scenarios. The effect of substrate temperature, electron beam power, and scan speed on the residual stress and deformation were examined. The numerical results show that a compressive plastic strain field forms in proximity to the melt pool. The model also indicates that within the temperature range of 630 ℃ to 730 ℃, a 50 ℃ increase in substrate temperature leads to a ~21% decrease in the in-elastic strain magnitude. Within the beam power range of 740 W to 940 W, the in-elastic strain decreased by ~9% with a 100 W increase in the beam power; and a ~23% increase in the in-elastic strain was observed with a 200 mm s⁻¹ increase in the beam speed.
View record
Experimental and numerical investigation of the effect of block-type support structure design on the thermal field within components fabricated by selective laser melting (2021)
The successful production of overhang features in the Selective Laser Melting (SLM) process requires additional structures, known as “support structures”. These structures provide mechanical support to overhang features and alter thermal fields within the produced components. Hence, the design of support structures impacts the development of in-situ thermal stress and component deformation. The present research combines experiments and numerical modelling to quantify the contribution of the support structure to the evolution of the thermal field in a cantilevered plate and, in turn, to investigate the relative role of heat transfer on component deformation. Series of build experiments were undertaken to investigate the effect of block-type support structure design on the deformation of the cantilevered plate. Two block-type support structures were designed for the overhang platform of a cantilevered plate. The designed samples were manufactured using SLM®500 machine located at Singapore Centre for 3-D Printing. The deformation of the overhang platform was measured using the Image Analysis technique. Next, a statistical analysis was performed to evaluate the relative impact of each design parameter on component deformation. Finally, a 2-D transient heat transfer model using the “layer agglomeration” approach was developed in the commercial package “ABAQUS” to perform a sensitivity analysis to investigate the impact of design parameters on heat transfer and the evolution of the thermal field in the support structure and the cantilevered plate. Numerical results demonstrated that the total contact area of teeth and the total support base area alter thermal fields within the produced components. It was predicted that increasing the area for conducting heat to the base reduces the peak temperature in the platform. Additionally, the vertical temperature gradient within the overhang platform decreased by increasing the total contact area of teeth. Moreover, increasing the total contact area of teeth produces a more uniform temperature field within the overhang platform, while the total base area was found to have a negligible impact on it. Also, the experimental case study was analyzed with the numerical thermal model suggested that the vertical temperature gradient and the peak temperature were reduced in the sample showing a lower amount of deformation.
View record
Fast to run model for thermal fields during metal additive manufacturing simulations (2020)
Additive Manufacturing simulations for thermal fields are computationally expensive because of the highly disparate length and time scales involved and can sometimes take days to run. Improving the speed of these simulations enables multiple virtual experiments to be run to understand the effects of various process parameters on heat buildup and can even be useful for in situ process control based on sensor measurements from the build area. The goal of this work is to reduce the computational time of such simulations while maintaining sufficient physics fidelity to yield reliable results. The approach taken is to replace the FEM model with a Fast-to-run (FTR) model which exploits the cyclic nature of the process to predict the thermal fields during AM. In this approach, peak temperatures and melt pools dimensions in a substrate melted by a moving heat source are modelled. The dependence of the heat transfer patterns on the heat source location and characteristics and the initial conditions of the substrate is modelled using data from the FEM simulation. Simulation time using the FTR model has been reduced significantly compared to the FEM simulation based on the domain size and time simulated. Finally, the FTR model is run on various complex scenarios. The effects of various hatching strategies are modelled and their maximum temperatures and melt depths are compared. Additionally, a slice of an impeller model is simulated using the FTR model to generate maximum temperature and melt depth maps, allowing the identification of hotspots and undermelted regions.
View record
Quantification of the Heat Transfer during the Plasma Arc Remelting of Titanium Alloys (2016)
Plasma-arc cold hearth melting (PAM) is an important technology used in the melting process for titanium alloys. Compared to the more common, electron beam cold hearth re-melting process, PAM allows an inert gas environment which significantly reduces the evaporation rate of alloying elements. To develop a better understanding of the effects of the plasma torch in the PAM process, a numerical model is being developed. However, this model requires an accurate description of the torch heat flux distribution. This research presented in this thesis focused on developing and verifying an inverse heat transfer analysis methodology to characterize the heat flux distribution from a plasma torch. A test block trial was conducted with in an industrial scale plasma arc furnace to measure the temperature history in a test block during heating and cooling. Following the trial, the test block was sectioned to get the liquid pool profile. The distribution of heat flux calculated from the inverse analysis assumed a Gaussian-like distribution, decreasing radially from the centerline to the edge of the block. Predictions for temperature history and liquid pool profile are in good agreement with the measured results from the experiment. Sensitivity analysis was performed to find some key factors that influence the prediction.
View record
Quantification of Cooling Channel Heat Transfer in the Low Pressure Die Casting (2014)
The focus of this project is to develop a methodology to quantitatively describe the heat transfer in the cooling channels of the low-pressure die casting process, which is the dominant commercial technology for the production of aluminum automotive wheels, and to successfully implement the methodology in a numerical model of the casting process. Towards this goal, an algorithm capable of calculating heat transfer coefficient (HTC) based on process parameters and surface temperature within the cooling channel is developed. The algorithm was implemented in the form of a user-defined subroutine in a 3-D thermal model of the Low Pressure Die Casting (LPDC) process developed in the commercial finite element analysis package in ABAQUS.The cooling channel HTC’s are often input into thermal models as an average constant value derived based on trial-and-error. The trial-and-error process to obtain the HTCs in the cooling channel involves, prescribing a trial set of HTC values and comparing the results of the casting simulation with thermocouple measurements. The trial cooling channel HTCs are then adjusted until a reasonable fit to the temperature measurements are achieved. The trial-and-error process is generally time consuming and does not accurately describe the physical phenomenon occurring in the cooling channel during casting. The constant cooling channel HTCs obtained through the trial-and-error process are tuned to a given set of operating conditions, compromising the utility and generality of the model.To provide data necessary for model validation, casting plant trials were performed at Canadian Autoparts Toyota Inc. in Delta, British Columbia. The trials included temperature measurements at pre-determined locations within the top, side and bottom dies. The validity of HTC calculations have been assessed by comparing the predicted temperature history of the subroutine-based model with the measured thermocouple data collected during the casting cycle and also comparing the model predictions with the base-case model with constant cooling channel HTC.
View record
Thermal mechanical analysis of interfacial behavior in aluminum allow wheel castin process (2014)
The focus of this project is to improve the understanding of the interfacial heat transfer behavior within the Low-Pressure Die Casting (LPDC) process, which is the main manufacturing process for A356 aluminum alloy wheels, and to develop an improved methodology/expression for calculating the heat transfer across the wheel/die interface. To formulate and assess expressions for the interfacial behavior, a 2D-axisymmetric coupled thermo-mechanical model has been developed in the commercial finite element package, ABAQUS. The model was capable of predicting the thermal history, deformation and the variation of the air gap and pressure along the wheel/die interface. The temperature predictions of the coupled thermo-mechanical model were compared with temperature measurements obtained at Canadian Auto Parts Toyota Inc obtained on a production die. A displacement measurement setup using a high temperature eddy current displacement sensor was designed and tested in a lab setting but not employed in a plant trial due timing issues.Initially, the coupled thermo-mechanical model was run with a temperature dependent interfacial heat transfer coefficient to obtain preliminary air gap and pressure behavior at various locations. Comparisons with the thermocouple measurements suggest that the model is able to generally qualitatively, and at some locations quantitatively, predict the temperature changes from the main physical phenomena occurring during the casting process. The preliminary air gap and pressure predictions were used to develop a temperature, gap size and pressure dependent interfacial heat transfer coefficient based on literature review. The interfacial heat transfer coefficient was implemented in the model, and was found to improve the agreement between the model predictions and measured temperatures, but was prone to numerical convergence issues.A new methodology of incrementally changing the interfacial heat transfer coefficient has been proposed to solve the issues. The methodology was implemented in an EXCEL spreadsheet to test it and the calculated interfacial heat transfer coefficients were found to be continuous, reflecting the effects of air gap and pressure evolution. The methodology and corresponding algorithm should be further developed for use in an ABAQUS model in the future.
View record
Modeling of Al evaporation and Marangoni flow in Electron Beam Button Melting of Ti-6Al-4V (2013)
The Electron Beam Cold Hearth Remelting (EBCHR) process has emerged as a key process in producing high quality Ti-6Al-4V ingot and electrode as it is able to effectively consolidate both sponge and scrap material while removing undesired impurities and inclusions, such as Low Density Inclusions (LDIs) and High Density Inclusions (HDIs). However, the challenge of composition control arises in processing alloys such as Ti-6Al-4V where evaporative loss of elements with higher vapor pressure (Al in this case) cannot be ignored. Therefore, in order to cast a product of specified composition, a thorough understanding of the evaporation mechanism and melt flow conditions becomes crucial in process control and optimization. This research presents a comprehensive model of the melt pool produced during Electron Beam Button Melting (EBBM) which has been developed to serve as an intermediate step in the development of a comprehensive tool for analysis and optimization of the industrial EBCHR process. With proper geometry and boundary conditions, the EBBM model can be readily applied to an industrial EBCHR furnace to minimize costly experiments in optimizing process parameters. A thermal-fluid-compositional model has been developed that includes Al evaporation, thermal and compositional buoyancy, thermal and compositional Marangoni flow and flow attenuation in the mushy regime. Experiments on Ti-6Al-4V and CP titanium with a circular electron beam pattern were conducted in a laboratory scale EBBM furnace in order to study the evaporation process and fluid flow in the liquid pool. The data obtained from the experimental work was used to tune the thermal boundary conditions and validate the model predictions. The temperature, surface velocity, pool profile and concentration profile have been experimentally quantified and used for validation of the mathematical model.
View record
Modeling of aluminum evaporation during electron beam cold hearth melting of titanium alloy ingots (2013)
Electron beam cold heart melting (EBCHM) is a consolidation and refining process capable of consolidating titanium scrap and sponge material into high quality titanium alloy ingots. Unlike other consolidation processes for titanium, EBCHM is efficient in removing both high and low density inclusions. During the final stage of casting in EBCHM, operators must balance the potential to form large shrinkage voids, caused by turning off the electron beam heating, against the tendency to evaporate alloying additions, which occurs if the top surface remains molten. To this end, a comprehensive understanding of the evaporation and fluid flow conditions occurring during the final stage of EBCHM is required in order to optimize ingot production. This research focused on developing a coupled thermal, fluid flow and composition model, capable of predicting the temperature, fluid flow and composition fields within an EBCHM cast, Ti-6Al-4V ingot. The physical phenomena of thermal and compositional buoyancy, mushy zone flow attenuation and aluminum evaporation were incorporated in the model formulation. Industrial scale experiments were carried out at the production facilities of a leading industrial producer of titanium to provide data and measurements used for model verification. The model has been used to study the effects of variation of electron beam power input and hot top time duration on the evaporative losses and position of solidification voids. Model predictions for liquid pool profile, last liquid to solidify and composition fields are in good agreement with the industrially measured results. Sensitivity analysis was performed by varying electron beam power and hot top duration independently and observing the effect on the composition fields and last liquid to solidify. For the cases examined, there was a strong correlation between electron beam power and alloying element losses, while hot top duration variation results indicated a stronger dependence on last liquid to solidify than on alloying element losses. Therefore a classic optimization problem arises between balancing hot top duration with alloying element losses.
View record
Physical and computational models of free surface related defects in low-pressure die-cast aluminum alloy wheels (2012)
The difference of die filling, which can be characterized by the free surface flow behavior, has a strong influence on the quality of casting components. In the case of cast aluminum alloy wheels, an undesired filling pattern with excessive turbulence can cause portions of the surface oxide film to be entrained within the bulk liquid resulting in defects such as cosmetic paint-pops, hot tears, porosity and rim-leaks. To investigate the influence of die filling on defect formation in low-pressure die-cast aluminum wheels, a water analogue physical model was built, instrumented and tested to simulate the free surface behavior during die filling of a low-pressure die-cast (LPDC) wheel. The physical model contains a transparent planar die section which was manufactured out of the geometry of a production die, and an automatic pressure control system that achieves liquid feeding conditions similar to the industrial process. A set of die filling tests with different venting conditions was carried out to explore the role of venting on the free surface behavior of water and to produce data for validation of a computational model. The computational model was developed, based on the commercial computational fluid dynamics code ANSYS CFX, for the purposes of predicting the flow conditions during die filling, providing qualitative and quantitative flow information that are otherwise not possible to obtain through experimental measurement, and identifying key features that influences the flow during die filling at a lower cost of time and labor. Comparison between the experimental and numerical data has shown that the computational model was able to qualitatively reproduce the flow behavior observed in the water model in the conditions tested. Both the experimental and the model results indicate that the entrainment of surface oxide films and air bubbles could occur at the outboard rim flange during the filling of the flange, below the free surface of the returning waves in the spoke and at the junction of the hub and the spoke during the filling of the hub. Venting conditions have been proved crucial and the importance of vent design in commercial die design was highlighted.
View record
Physical and Computational Models of Marangoni and Buoyancy Flow During Dissolution (2012)
During the production of titanium products, the presence of aluminum-rich regions can cause Type II alpha stabilized defects which are deleterious to down-stream performance. Al-rich material can enter the melt via ballistic transfer from the melting hearth at various stages during electron beam cold hearth re-melting (EBCHR) of Ti-6Al-4V (Ti-6wt%Al-4wt%V) alloy. If this material is not fully dissolved and homogenized when solidification occurs, the ingot will contain Al-rich regions. Thus, in order to produce high-performance components for aerospace applications, titanium producers must understand the dissolution process for alloying elements entering the melt. To study and characterize the phenomena associated with the dissolution and homogenization of alloying elements during EBCHR processing of Ti-6Al-4V, a water-ethanol physical analogue model has been developed to simulate the thermal, compositional and fluid flow behavior that are active in the dissolution process. The physical model consists of a hot water solvent contained in a transparent cell (beaker) in which solidified ethanol or ice solute is dipped. The data generated from the physical model was used to validate a coupled thermal- fluid flow-composition model (developed in the commercial CFD code ANSYS CFX).The analogue model focuses on characterizing the effects of thermal and compositional variations on surface tension driven fluid flow (Marangoni flow) and buoyancy driven flow during the dissolution of a low density, low surface tension and low melting point solid material (frozen ethanol) in a high density, high surface tension and high melting point liquid (water), which was found to be analogous to the dissolution of solid Al in liquid Ti. In addition, the analogue model was also capable to predict the dissolution behavior when there was no compositional difference between the solute and the solvent. Based on a comparison of fluid flow pattern and interface shape, and temperature data obtained at discrete locations in the experimental and computational results, the numerical model has been shown to quantitatively and qualitatively predict the dissolution behavior observed in the physical process.
View record
Factors Influencing the Fluid Flow and Heat Transfer in Electron Beam Melting of Ti-6Al-4V (2010)
Electron Beam Cold Hearth Remelting (EBCHR) and its associated casting process is an important consolidation technique for the treatment of virgin titanium sponge and scrap. The development of robust models to describe the casting process hinge on accurately capturing heat transfer phenomena within the ingot and fluid flow phenomena within the liquid pool. The flow field that develops within the liquid pool is influenced by several factors including buoyancy driven flow due to thermal gradients within the pool, surface tension, or Marangoni, driven flow due to the large thermal gradients induced on the surface by the Electron Beam and the ability of the mushy, or semi-solid, zone to attenuate the flow. A mathematical model describing fluid flow and heat transfer in a Ti6Al4V button sample during electron beam melting has been developed to examine the relative contribution of the three factors cited above on the pool profile and flow field within the pool. The model has also been used to compare the steady state solution for a time averaged circular beam pattern with a transient solution obtained for the case where the beam pattern is comprised of a series of discrete points scribing the same circle. The latter, in which the beam spot is periodically stationary for small but finite periods, is intended to more closely mimic the industrial process.The model is also used to examine the sensitivity of the predictions to changes in numerical and process parameters. The results indicate that the electron beam power and heat transfer coefficient have the largest influence on the liquid pool profile while the surface tension coefficient has little effect (i.e. 25% change in electron beam power results in ~25% liquid pool profile while 100% change in time step results in less than 1% in prediction).
View record
Heat transfer characterization of secondary cooling in the horizontal direct chill casting process for aluminum alloy re-melt ingot (2010)
Horizontal direct chill (HDC) casting is a continuous process used to produce extrusion billet and re-melt aluminum ingot. As in vertical DC casting, secondary cooling, where water directly impinges on the cast surface, is an important process that can affect cast quality and production rates. During HDC casting, secondary cooling is further complicated by horizontal water flow and the water spray conditions. Characterizing the heat transfer during the secondary cooling process is necessary for improved understanding of the process. Since the accessibility of the HDC casting machine is limited and the direct measurement of heat transfer in secondary cooling are difficult, numerical modeling thus becomes a good approach for process development.In this research, the heat transfer occurring in secondary cooling of an HDC ingot has been studied. Water spray conditions on three different casting surface were simulated separately by quenching the blocks of HDC cast A356 aluminum alloy which was cut from a T-ingot. The temperature history during the cooling within the blocks was recorded by sub-surface thermocouples. An inverse heat transfer model was developed and used to calculate the heat fluxes on the casting surfaces using measured temperature data. The heat fluxes were characterized via boiling curves, which are the functions of surface temperatures, in each spray configuration.The effects of operational parameters, including the casting speed and the water cooling rate, were investigated by comparing the characteristic features of the calculated boiling curves. The spray configuration effect was also studied with the calculated results from the stationary tests in a qualitative fashion.Then a fitting technique was developed to idealize the calculated boiling curves. The idealized boiling curves were summarized into the functions,which provide practical database for application of the results in this research.All in all, the simulation apparatus and the IHC model provide the ability of characterizing the heat transfer occurring in secondary cooling region of HDC casting with lab-scale experiments. Consequently, the expensive and risky plant trials can be avoided.
View record
Publications
- An improved thermomechanical model for the prediction of stress and strain evolution in proximity to the melt pool in powder bed fusion additive manufacturing (2025)
COMPUTATIONAL MECHANICS, - Development of a bench-scale Kroll reactor: Experimental results and preliminary findings (2025)
Results in Engineering, - Passive Layer Evolution of Anodized B206 Aluminum in Seawater for Tidal Energy Applications: An Electrochemical Approach (2025)
METALS, - A new variant of the inherent strain method for the prediction of distortion in powder bed fusion additive manufacturing processes (2024)
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, - Incorporating non-linear effects in fast semi-analytical thermal modelling of bed fusion (2024)
ADDITIVE MANUFACTURING, - Incorporating non-linear effects in fast semi-analytical thermal modelling of powder bed fusion (2024)
Arxiv, - Numerical-Experimental Assessment of the Semi-Solid Contraction Behavior of Grain-Refined High Strength Aluminum Alloy, B206 (2024)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - A macroscale heat transfer analysis of the build chamber in a commercial electron beam powder bed fusion (EB-PBF) additive manufacturing system during component fabrication (2023)
ADDITIVE MANUFACTURING, - A macroscale heat transfer analysis of the build chamber in a commercial electron beam powder bed fusion (EB-PBF) additive manufacturing system during component fabrication (2023)
Additive Manufacturing, - A novel approach for the numerical analysis of in situ distortion in a component made by the directed energy deposition additive manufacturing process (2023)
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, - Comparison of Semi-Solid Contraction of Aluminum Alloys During Solidification Quantified by a Combined Numerical-Experimental Approach (2022)
METALS AND MATERIALS INTERNATIONAL, - Development of a Machine Learning Model to Predict Constitutive Behaviour of Macrosegregated A356 Alloy (2022)
LIGHT METALS 2022, - Dissolution of Ti-N inclusions in liquid titanium during electron beam melting (2022)
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T, - Quantitative Assessment of Operational Parameters on Die Temperature During an Industrial Low-Pressure Die Casting Process (2022)
LIGHT METALS 2022, - Study of an Industrial Scale Counter Pressure Casting Process Using an Advanced Thermal-Stress Model (2022)
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, - The role of block-type support structure design on the thermal field and deformation in components fabricated by Laser Powder Bed Fusion (2022)
ADDITIVE MANUFACTURING, - A study of an industrial counter pressure casting process for automotive parts (2021)
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T, - A thermal-stress modelling methodology in ABAQUS for fundamentally describing the die/ casting interface behaviour in a cyclic permanent die casting process (2021)
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T, - Diffusion of nitrogen in solid titanium at elevated temperature and the influence on the microstructure (2021)
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T, - Numerical modeling of the diffusional transport of nitrogen in multi-phase solid titanium and its application to determine diffusion coefficients (2021)
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T, - A fully-coupled thermal-stress model to predict the behavior of the casting-chill interface in an engine block sand casting process (2020)
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, - Advanced Process Simulation of Low Pressure Die Cast A356 Aluminum Automotive Wheels-Part I, Process Characterization (2020)
METALS, - Advanced Process Simulation of Low Pressure Die Cast A356 Aluminum Automotive Wheels-Part II Modeling Methodology and Validation (2020)
METALS, - Effect of Weld Parameters on the Microstructure of Aluminum-Copper Joints Produced by Flash Welding (2020)
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, - Investigation of the efficacy of a water-cooled chill on enhancing heat transfer at the casting-chill interface in a sand-cast A319 engine block (2020)
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, - Meso-scale modelling of semi-solid deformation in aluminum foundry alloys: Effects of feeding and microstructure on hot tearing susceptibility (2020)
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, - Modelling of an industrial die casting process for the production of aluminum automotive parts (2020)
INTERNATIONAL CONFERENCE ON MODELLING OF CASTING, WELDING AND ADVANCED SOLIDIFICATION PROCESSES (MCWASP XV), - Toward the development of a thermal-stress model of an industrial counter pressure casting process (2020)
INTERNATIONAL CONFERENCE ON MODELLING OF CASTING, WELDING AND ADVANCED SOLIDIFICATION PROCESSES (MCWASP XV), - A Study of the Mass Transfer Kinetics during the Dissolution of Ti-N Particles in Liquid Titanium (2019)
JOINT 5TH INTERNATIONAL CONFERENCE ON ADVANCES IN SOLIDIFICATION PROCESSES (ICASP-5) & 5TH INTERNATIONAL SYMPOSIUM ON CUTTING EDGE OF COMPUTER SIMULATION OF SOLIDIFICATION, CASTING AND REFINING (CSSCR-5), - An investigation of the chill-casting interface dynamics in production of sand-cast A319 engine blocks (2019)
JOINT 5TH INTERNATIONAL CONFERENCE ON ADVANCES IN SOLIDIFICATION PROCESSES (ICASP-5) & 5TH INTERNATIONAL SYMPOSIUM ON CUTTING EDGE OF COMPUTER SIMULATION OF SOLIDIFICATION, CASTING AND REFINING (CSSCR-5), - Characterization of heat transfer and its effect on solidification in water cooled LPDC of wheels (2019)
JOINT 5TH INTERNATIONAL CONFERENCE ON ADVANCES IN SOLIDIFICATION PROCESSES (ICASP-5) & 5TH INTERNATIONAL SYMPOSIUM ON CUTTING EDGE OF COMPUTER SIMULATION OF SOLIDIFICATION, CASTING AND REFINING (CSSCR-5), - Comparison of the semi-solid constitutive behaviour of A356 and B206 aluminum foundry alloys (2019)
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, - Porosity Prediction in A356 Wheel Casting (2019)
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, - Effect of retrogression and re-aging (RRA) heat treatment on the corrosion behavior of B206 aluminum-copper casting alloy (2018)
MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION, - Examination and Simulation of Silicon Macrosegregation in A356 Wheel Casting (2018)
METALS, - Quantification of heat transfer phenomena within the melt pool during the plasma arc re-melting of titanium alloys (2018)
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, - Quantification of the heat transfer during the plasma arc re-melting of titanium alloys (2018)
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, - Through process Modeling applied to the fatigue design of cast A356-T6 components (2018)
ENGINEERING FRACTURE MECHANICS, - Through Process Modelling applied to the fatigue resistance of cast Aluminum (2018)
7TH INTERNATIONAL CONFERENCE ON FATIGUE DESIGN, FATIGUE DESIGN 2017, - A Combined Numerical-Experimental Approach to Quantify the Thermal Contraction of A356 During Solidification (2017)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Characterization of macrosegregation in eutectic alloys (2017)
MATERIALS CHARACTERIZATION, - Experimental Procedure for Warm Spinning of Cast Aluminum Components (2017)
JOVE-JOURNAL OF VISUALIZED EXPERIMENTS, - FIB/SEM Study of Pitting and Intergranular Corrosion in an Al-Cu Alloy (2017)
CORROSION, - A three-dimensional transient thermal-fluid flow-compositional study of ingot casting during electron beam remelting of Ti-6Al-4V (2016)
APPLIED MATHEMATICAL MODELLING, - Modelling the constitutive behaviour of aluminium alloy B206 in the as-cast and artificially aged states (2016)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - An examination of the factors influencing the melting of solid titanium in liquid titanium (2015)
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, - Analysis and modelling of a rotary forming process for cast aluminium alloy A356 (2015)
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, - Analysis and modelling of a rotary forming process for cast aluminum alloy A356 (2015)
Arxiv, - Application of Numerical Optimization to Aluminum Alloy Wheel Casting (2015)
MCWASP XIV: INTERNATIONAL CONFERENCE ON MODELLING OF CASTING, WELDING AND ADVANCED SOLIDIFICATION PROCESSES, - Development of an Optimization Methodology for the Aluminum Alloy Wheel Casting Process (2015)
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, - Influence of casting defect and SDAS on the multiaxial fatigue behaviour of A356-T6 alloy including mean stress effect (2015)
INTERNATIONAL JOURNAL OF FATIGUE, - Microstructure Characterization and Thermal Analysis of Aluminum Alloy B206 During Solidification (2015)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Study of melting mechanism of a solid material in a liquid (2015)
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, - A three-dimensional steady state thermal fluid model of jumbo ingot casting during electron beam re-melting of Ti-6Al-4V (2014)
APPLIED MATHEMATICAL MODELLING, - An Examination of the Thermally Related Factors Influencing the Melting/Dissolution of Solids in Liquid Titanium (2014)
TMS 2014 SUPPLEMENTAL PROCEEDINGS, - Effect of chill cooling conditions on cooling rate, microstructure and casting/chill interfacial heat transfer coefficient for sand cast A319 alloy (2014)
INTERNATIONAL JOURNAL OF CAST METALS RESEARCH, - Fatigue characterization of flowformed A356-T6 (2014)
FDMD II - JIP 2014 - FATIGUE DESIGN & MATERIAL DEFECTS, - Mean stress effect under Multi-Axial High Cycle Fatigue loading for cast A356-T6 alloy (2014)
FDMD II - JIP 2014 - FATIGUE DESIGN & MATERIAL DEFECTS, - MODELING CRACKING IN REFRACTORY MATERIALS DUE TO THERMAL CYCLING (2014)
PROCEEDINGS OF THE UNIFIED INTERNATIONAL TECHNICAL CONFERENCE ON REFRACTORIES (UNITECR 2013), - Multiaxial Fatigue Behaviour of A356-T6 (2014)
Arxiv, - Response of A356 to warm rotary forming and subsequent T6 heat treatment (2014)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Constitutive behavior of as-cast A356 (vol 548, pg 195, 2012) (2013)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Development of a 3D Filling Model of Low-Pressure Die-Cast Aluminum Alloy Wheels (2013)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Process Modeling of Low-Pressure Die Casting of Aluminum Alloy Automotive Wheels (2013)
JOM, - Analytical solution of the tooling/workpiece contact interface shape during a flow forming operation (2012)
Arxiv, - Computational Modeling of the Dissolution of Alloying Elements (2012)
TMS 2012 141ST ANNUAL MEETING & EXHIBITION - SUPPLEMENTAL PROCEEDINGS, VOL 1: MATERIALS PROCESSING AND INTERFACES, - Constitutive behavior of as-cast A356 (2012)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Modeling and Optimizing Ti-6Al-4V Ingot Production (2012)
MCWASP XIII: INTERNATIONAL CONFERENCE ON MODELING OF CASTING, WELDING AND ADVANCED SOLIDIFICATION PROCESSES, - Modeling of as-cast A356 for coupled explicit finite element analysis (2012)
LIGHT METALS 2012, - Modeling of Die Filling of Low-Pressure Die-Cast Aluminum Alloy Wheels (2012)
TMS 2012 141ST ANNUAL MEETING & EXHIBITION - SUPPLEMENTAL PROCEEDINGS, VOL 2: MATERIALS PROPERTIES, CHARACTERIZATION, AND MODELING, - Multiaxial Kitagawa analysis of A356-T6 (2012)
Arxiv, - Nonlinear Identification for Control of Low Pressure Die Casting (2012)
2012 AMERICAN CONTROL CONFERENCE (ACC), - Permeability evolution during equiaxed dendritic solidification of Al-4.5wt% Cu (2012)
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, - Determination of optimal location to monitor temperature in low pressure die casting process (2011)
MATERIALS SCIENCE AND TECHNOLOGY, - IDENTIFICATION FOR CONTROL OF LOW PRESSURE DIE CASTING (2011)
PROCEEDINGS OF THE ASME INTERNATIONAL MANUFACTURING SCIENCE AND ENGINEERING CONFERENCE 2010, VOL 2, - Inverse Analysis of Eutectic Nucleation and Growth Kinetics in Hypoeutectic Al-Cu Alloys (2011)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Permeability of dual structured hypoeutectic aluminum alloys (2011)
ACTA MATERIALIA, - Physical and Computational Models of Free Surface Related Defects in Low-Pressure Die-Cast Aluminum Alloy Wheels (2011)
SHAPE CASTING: 4TH INTERNATIONAL SYMPOSIUM 2011 IN HONOR OF PROF. JOHN T. BERRY, - PHYSICAL CHARACTERIZATION OF THE PEREMABILITY OF EQUIAXED EUTECTIC STRUCTURES IN HYPOEUTECTIC ALUMINUM ALLOYS (2011)
SHAPE CASTING: 4TH INTERNATIONAL SYMPOSIUM 2011 IN HONOR OF PROF. JOHN T. BERRY, - Study of Microporosity Formation under Different Pouring Conditions in A356 Aluminum Alloy Castings (2011)
LIGHT METALS 2011, - MODELING THE EFFECT OF EUTECTIC NUCLEATION BEHAVIOR ON PERMEBILITY DURING SOLIDIFICATION OF Al-19.5wt%Cu (2010)
TMS 2010 139TH ANNUAL MEETING & EXHIBITION - SUPPLEMENTAL PROCEEDINGS, VOL 2: MATERIALS CHARACTERIZATION, COMPUTATION AND MODELING AND ENERGY, - Modeling the Stress-Strain Behavior and Hot Tearing during Direct Chill Casting of an AZ31 Magnesium Billet (2010)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Numerical determination of permeability of Al-Cu alloys using 3D geometry from X-ray microtomography (2010)
MATERIALS SCIENCE AND TECHNOLOGY, - Physical and numerical characterization of the near-eutectic permeability of aluminum-copper alloys (2010)
ACTA MATERIALIA, - An investigation of predictive control for aluminum wheel casting via a virtual process model (2009)
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, - Constitutive behavior of as-cast magnesium alloy Mg-Al3-Zn1 in the semi-solid state (2009)
SCRIPTA MATERIALIA, - Investigation of residual strains by neutron diffraction in an AZ31 direct chill cast billet (2009)
NDT & E INTERNATIONAL, - MODELING OF POROSITY SIZE DISTRIBUTION IN A356 TAPERED CYLINDER CASTINGS (2009)
MODELING OF CASTING, WELDING, AND ADVANCED SOLIDIFICATION PROCESSES - XII, - MODELING THE FORMATION OF POROSITY DURING LOW PRESSURE DIE CASTING (LPDC) OF ALUMINUM ALLOY A356 (2009)
SHAPE CASTING: 3RD INTERNATIONAL SYMPOSIUM 2009, - Modelling of the cyclic behaviour of shape memory alloys during localized unstable mechanical response (2009)
SMART MATERIALS AND STRUCTURES, - NUMERICAL MODELING OF PERMEABILITY OF ALLUMINUM-COPPER ALLOYS USING 3D MICROTOMOGRAPHIC GEOMETRY (2009)
EPD CONGRESS 2009, PROCEEDINGS, - Quantification of the interaction within defect populations on fatigue behavior in an aluminum alloy (2009)
ACTA MATERIALIA, - X-Ray Microtomographic Characterization of Porosity in Aluminum Alloy A356 (2009)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Application of a mathematical model to multipass hot deformation of aluminium alloy AA5083 (2008)
MATERIALS SCIENCE AND TECHNOLOGY, - Finite element modeling of the thermo-mechanical behavior of an AZ31 magnesium alloy during hot rolling (2008)
MAGNESIUM TECHNOLOGY 2008, - FINITE ELEMENT SIMULATION OF STRAIN RATE EFFECTS ON LOCALIZED UNSTABLE PSEUDOELASTIC RESPONSE OF SHAPE MEMORY ALLOYS (2008)
JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES, - Modeling of the cyclic behavior of shape memory alloys during localized unstable mechanical response (2008)
MULTI-FUNCTIONAL MATERIALS AND STRUCTURES, PTS 1 AND 2, - A through process model of the impact of in-service loading, residual stress, and microstructure on the final fatigue life of an A356 automotive wheel (2007)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Development of a 3-D thermal model of the low-pressure die-cast (LPDC) process of A356 aluminum alloy wheels (2007)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Mathematical modeling of multipass hot deformation of aluminum alloy AA5083 - Model development and validation (2007)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Modeling the investment casting of a titanium crown (2007)
DENTAL MATERIALS, - Multi-dimensional constitutive modeling of SMA during unstable pseudoelastic behavior (2007)
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, - Simulating the residual stress in an A356 automotive wheel and its impact on fatigue life (2007)
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, - The effect of mould flux properties on thermo-mechanical behaviour during billet continuous casting (2007)
ISIJ INTERNATIONAL, - A thermal model of the Low-Pressure Die-Casting (LPDC) process and its application to predict porosity formation in aluminum alloy wheels (2006)
SIMULATION OF ALUMINUM SHAPE CASTING PROCESSING: FROM ALLOY DESIGN TO MECHANICAL PROPERTIES, - A validated model of the cyclic stress state of an A356 automotive wheel and its impact on fatigue life (2006)
SIMULATION OF ALUMINUM SHAPE CASTING PROCESSING: FROM ALLOY DESIGN TO MECHANICAL PROPERTIES, - A validated through process model to predict the fatigue life of a cast A356 automotive wheel (2006)
ALUMINIUM ALLOYS 2006, PTS 1 AND 2, - Application of a mathematical model to simulate multi-pass hot rolling of aluminum alloy AA5083 (2006)
ALUMINIUM ALLOYS 2006, PTS 1 AND 2, - Investigation of erosive-corrosive wear in the low pressure die casting of aluminum A356 (2006)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Modeling of microporosity formation in A356 aluminum alloy casting (2006)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Multi-dimensional thermomechanical model for pseudoelastic response of SMA (2006)
SMART STRUCTURES AND MATERIALS 2006: MODELING, SIGNAL PROCESSING, AND CONTROL, - One-dimensional thermomechanical model for dynamic pseudoelastic response of shape memory alloys (2006)
SMART MATERIALS AND STRUCTURES, - Prediction of fatigue performance in cast aluminum alloy components (2006)
SIMULATION OF ALUMINUM SHAPE CASTING PROCESSING: FROM ALLOY DESIGN TO MECHANICAL PROPERTIES, - Understanding T-ingot horizontal DC casting using process modelling (2006)
ALUMINIUM ALLOYS 2006, PTS 1 AND 2, - X-ray microtomographic characterisation of porosity and its influence on fatigue crack growth (2006)
ADVANCED ENGINEERING MATERIALS, - A mathematical model of heat transfer and fluid flow in the direct chill casting of AZ31 magnesium billets (2005)
MAGNESIUM TECHNOLOGY 2005, - Casting Defects in Low-Pressure Die-Cast Aluminum Alloy Wheels (2005)
JOM, - Implementation of a strain-based hot tearing criterion in direct chill cast aluminum ingots (2005)
LIGHT METALS 2005, - Mathematical modeling of residual stress formation in electron beam remelting and refining of scrap silicon for the production of solar-grade silicon (2005)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Prediction and measurement of residual stresses/strains in a direct chill casting magnesium alloy billet (2005)
MAGNESIUM TECHNOLOGY 2005, - Quantification of temperature, stress, and strain fields during the start-up phase of direct chill casting process by using a 3D fully coupled thermal and stress model for AA5182 ingots (2005)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Simulation of microporosity in A356 aluminium alloy castings (2005)
INTERNATIONAL JOURNAL OF CAST METALS RESEARCH, - A through-process model of an A356 brake caliper for fatigue life prediction (2004)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Constitutive behaviour of A356 during the quenching operation (2004)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Development and validation of a thermal model of the direct chill casting of AZ31 magnesium billets (2004)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Improved gyratory crushing operation by the assessment of liner wear and mantle profile redesign (2004)
MINERALS ENGINEERING, - Liner wear and performance investigation of primary gyratory crushers (2004)
MINERALS ENGINEERING, - On the development of a three-dimensional transient thermal model to predict ingot cooling behavior during the start-up phase of the direct chill-casting process for an AA5182 aluminum alloy ingot (2004)
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, - Tensile properties of AS-cast AA5182 aluminum alloy close to the solidus temperature (2004)
SOLIDIFICATION OF ALUMINUM ALLOYS, - Tensile properties of as-cast aluminum alloy AA5182 close to the solidus temperature (2004)
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, - Thermal modeling of direct chill casting for AZ31 magnesium billets (2004)
LIGHT METALS AND METAL MATRIX COMPOSITES, - A sensitivity analysis of the work roll-strip interface parameters used during modelling of hot rolling for AA5083 (2003)
HOT DEFORMATION OF ALUMINUM ALLOYS III, - Mathematical model of deformation and microstructural evolution during hot rolling of aluminium alloy 5083 (2003)
MATERIALS SCIENCE AND TECHNOLOGY, - Mathematical modelling of water ejection and water incursion during the start-up phase of the DC casting process (2003)
LIGHT METALS 2003, - Modeling of microporosity formation during solidification of A356 aluminum casting (2003)
LIGHT METALS 2003, - Thermomechanical analysis of the DC casting process for AA5182 billets - Comparison of solid state constitutive laws on model predictions of strain and butt curl (2003)
LIGHT METALS 2003, - Crack defect formation during manufacture of fused cast alumina refractories (2002)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Development of a mathematical model using ABAQUS to simulate industrial hot tandem rolling of AA5XXX aluminum alloys (2001)
EPD CONGRESS 2001, - Mathematical modeling of heat transfer and microporosity formation in die cast A356 wheels (2001)
COMPUTATIONAL MODELING OF MATERIALS, MINERALS AND METALS PROCESSING, - Mathematical modeling of microporosity in A356 aluminum die-castings (2001)
LIGHT METALS 2001, - Mathematical modelling of the thermomechanical behavior of a 5182 aluminum ingot during the start-up phase of the DC casting process: The role of bottom block (2001)
LIGHT METALS 2001, - A two-dimensional model for the description of the columnar-to-equiaxed transition in competing gray and white iron eutectics and its application to calender rolls (2000)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Modeling of microstructure and residual stress in cast iron calender rolls (2000)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, - Mathematical modeling of microstructural development in hypoeutectic cast iron (1999)
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE,
If this is your researcher profile you can log in to the Faculty & Staff portal to update your details and provide recruitment preferences.
Membership Status
Program Affiliations
Academic Unit(s)
