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Seminar Notice for Joseph Anderson's Preliminary Exam. Friday, Dec. 13, at 9:30 a.m., in ARMS 1021 "The Statistical Mechanics of Interacting Particles (With Applications in Dislocation Dynamics)”
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR “The Statistical Mechanics of Interacting Particles (With Applications in Dislocation Dynamics)” By Joseph P. Anderson Purdue MSE Preliminary Exam Advisor: Professor Anter A. El-Azab ABSTRACT The dynamics of smooth density fields of discrete entities (e.g. electrons, fluid particles, dislocations) depend strongly on the short-range order of the underlying discrete entities considered. Statistical mechanics presents a means of determining this short-range order from the interaction potential. However, the means by which that is accomplished is not straightforward. In this presentation we will discuss the extension of statistical mechanics to interacting systems, and how this short-range order emerges in the equilibrium of such a system. This involves such topics as the Born-Bogoliubov-Green-Kirkwood-Yvon (BBGKY) hierarchy of densities (of which the radial distribution function [cid:image002.png@01D5AEAE.52D8F370] is a special case) and closure approximations to this hierarchy. By means of a geometric interpretation of the ergodic theorem, we will examine under which regimes of interaction strength these methods may be applied, as well as the two-temperature models used to work around issues of ergodicity. Finally, we will discuss how dynamic theories which hold well beyond equilibrium may be formed from a description of short-range structures. This discussion will include projection operator approaches, as well as a formalism known as the General Equation for Non-Equilibrium Reversible Irreversible Coupling (GENERIC). Throughout, we will discuss the application of these ideas to the topic of dislocation dynamics, as well as the issues which arise in that application. . Date: Wednesday, December 13, 2019 Time: 8:00 A.M. Place: ARMS 1021

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Seminar Notice for Saswat Mishra. Dec. 12, at 9:00 a.m., in ARMS 1103 "First-principles Approach to Model Point Defects in Materials and Predict their Corresponding Thermodynamic Transition States"
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "First-principles Approach to Model Point Defects in Materials and Predict their Corresponding Thermodynamic Transition States" By Saswat Mishra Purdue MSE Preliminary Exam Advisor: Professor Alejandro Strachan ABSTRACT Defects are ubiquitous in materials and affect their physical, structural, chemical, and electrical properties. It is difficult to detect electronic states far from the band edge experimentally, and hence a few defect levels are challenging to characterize. First-principles study of defects can provide crucial insight into the position of these electronic trap states by complimenting experimentally observed states. However, the potential of a charged system under periodic boundary conditions diverges. Various techniques have been suggested to model charged defects using density functional theory (DFT), which use approximations to determine the energy. These approximations introduce spurious effects and taint the result, which can be corrected using various schemes. This work aims to compare two such correction schemes applied to a simple Silicon vacancy system and comment upon the predictability of the approaches. Date: Thursday, December 12, 2019 Time: 9:00 A.M. Place: ARMS 1103

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Seminar Notice for Yujie Wang's Preliminary Exam. Wednesday, Dec. 11, at 12:00, in ARMS 1103 The review and exam will also be in ARMS 1103
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Oxidation Kinetics of the Cr2AlC MAX Phase" By Yujie Wang Purdue MSE Preliminary Exam Advisor: Professor Kenneth H. Sandhage ABSTRACT Currently, the MAX phase materials have received significant attention from scientists because of their promising practical application. The unique nano-layered structure provides a useful combination of metallic and ceramic properties. For example, MAX phases are typically characterized as being thermally and electrically conductive, plastically deformable, machinable, and thermal shock resistant like metals; as well as having high elastic moduli, excellent high-temperature mechanical properties, and good oxidation and hot corrosion resistance like ceramics. Among all the MAX phases, Cr2AlC is a thermodynamically stable ternary compound with hexagonal structure. The chromium aluminium carbide (Cr2AlC) exhibits excellent mechanical properties and good oxidation and hot corrosion resistance due to the formation of dense adherent α-Al2O3 protective layer. All those unique properties along with the excellent oxidation resistance make Cr2AlC an attractive material for high-temperature applications. However, it will be necessary to understand the oxidation mechanism and corresponding kinetics of Cr2AlC in order to predict the long-time performance at elevated temperatures. This is, in turn, implies that the oxidation kinetics need to be well understood. However, the kinetic behavior of Cr2AlC is still under controversy. In this document, the mechanisms of isothermal oxidation of Cr2AlC will be studied, and the corresponding rate-limiting steps would be reviewed. Date: Wednesday, December 11, 2019 Time: 12:00 P.M. Place: ARMS 1103

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MSEE & ARMS Lab Classifications
by MSE Safety 09 Dec '19

09 Dec '19

Hello MSE Researchers, Here is a spreadsheet of MSEE & ARMS lab classifications and their PIs as requested by a few students. I hope this is helpful. Regards, Jenni

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Seminar Notice for Amrita Sen Wednesday, Dec. 11 at 12:30, in ARMS 1021. Review will be at 2:30 (for the student) Exam will begin at 3:00 All in ARMS 1021
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Atom Probe Tomography of Bulk Oxides" By Amrita Sen Purdue MSE Preliminary Exam Advisors: Professor Anter A. El-Azab and Professor Janelle P. Wharry ABSTRACT Atom Probe Tomography (APT) is a 3D microscopy technique that can provide atom-byatom spatial and chemical quantification of a needle-shaped sample. The technique is well established for use with metals. However, APT of oxide/semiconductor/insulating materials is not trivial. This review will specifically focus on APT of bulk oxides. The optical and absorption properties of oxide materials influence whether successful laser absorption, field evaporation, and accurate chemical quantification of the material can be achieved with this technique. Factors such as laser energy and laser wavelength influence field evaporation and measured chemistry, and therefore must be optimized for each oxide respectively. This paper will review previous parametric studies of bulk oxides with APT and seek to identify any trends in field evaporation behavior and chemical analysis of these types of materials with this technique. Date: Wednesday, December 11, 2019 Time: 12:30 P.M. Place: ARMS 1021 School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2200 West Lafayette, IN 47907 765-494-4105 [PU150]

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Seminar Notice for Yifan Wu's Preliminary Exam. Seminar, Wednesday, Dec. 11, at 8:00 a.m., in ARMS 1109
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Liquid Metal Embrittlement Induced by Gallium-based Liquid Metal" By Yifan Wu Purdue MSE Preliminary Exam Advisors: Professor Carol A. Handwerker and Professor John E. Blendell ABSTRACT Liquid metal embrittlement (LME) is a phenomenon in which a normally ductile metal or alloy experiences loss of ductility when stressed while in contact with a liquid metal. Ga is of particular interest in the study of LME due to its relatively low melting point. Although LME has been discovered for over a century, the mechanism behind is yet fully understood. Current consensus on the occurrence of LME is decrease in interatomic bond strength induced by the adsorption of liquid metal. Recent progress in nanoscale characterization techniques, such as synchrotron X-ray radiography and in situ TEM shows that the Ga penetration-induced dislocation movement and localized plasticity at the penetration front of gallium. Advanced synchrotron X-ray tomography reveals the dependence of Ga liquid metal penetration on grain boundary energy. Computational methods provide an alternative approach in studying LME at an atomic scale. Atomistic simulation results show the effect of applied stress on grain boundary penetration at an atomistic scale as well as dislocation movement along the grain boundary. A new model, dislocation climb model, was proposed based on this observation to explain the occurrence and propagation of cracks in LME. Key words: Liquid metal embrittlement, gallium liquid metal, grain boundary penetration Date: Wednesday, December 11, 2019 Time: 8:00 A.M. Place: ARMS 1109 School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2200 West Lafayette, IN 47907 765-494-4105 [PU150]

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Seminar Notice for Cole Davis Wednesday, Dec. 11, 9:30 a.m., in ARMS 1021"Formation and Stability of Surfactant-Stabilized, Spontaneous, Oil-in-Water Emulsions in Saline Environments"
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Formation and Stability of Surfactant-Stabilized, Spontaneous, Oil-in-Water Emulsions in Saline Environments" By Cole R. Davis Purdue MSE Preliminary Exam Advisors: Professor Carlos J. Martinez and Professor Kendra A. Erk ABSTRACT Spontaneous emulsification provides a low energy alternative to forming nano-sized emulsions in pharmaceuticals, enhanced oil recovery, detergency, and more. Although this method can be advantageous, spontaneous emulsification can be problematic in systems where oil and water mixtures are undesirable. These systems include wastewater and can introduce harmful oils (e.g., aromatics) into the environment. Literature involving spontaneous emulsification provides mechanisms for how these emulsions form, but little is done to precisely control the occurrence or rate of spontaneous emulsification. Furthermore, few papers exist that include the presence of salts during emulsification, which is highly relevant to many wastewater systems including bilge water. This study investigates the formation of spontaneous oil-in-water emulsions in saline environments and proposes the following hypothesis: the presence of salts found in seawater will act to promote spontaneous emulsification and may increasing the stability of surfactant-stabilized oil-in-water emulsions. To test this hypothesis, dynamic light scattering will be used to quantify the rate of emulsification for a variety of surfactant-oil-saltwater mixtures. Salinities will be selected based on calculated optimal salinity values where the hydrophilic lipophilic difference (HLD) is zero. Surfactant concentrations will also vary according to their respective critical micelle concentrations (CMCs) at different salinities to test the need for the presence of surfactant micelles during spontaneous emulsification. This work will provide a deeper understanding on the formation and stability of spontaneous emulsions in saltwater systems with the goal of building a model, based on the HLD model, that can be used to predict and ultimately prevent spontaneous emulsification in wastewater systems. Date: Wednesday, December 11, 2019 Time: 9:30 A.M. Place: ARMS 1021

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Seminar Reminder for Michael Park's Preliminary Exam. Seminar, Tuesday, Dec. 10, at 9:00 a.m., in ARMS 1021 "Perovskite Nickelate ReRAM for Next Generation Memory"
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Perovskite Nickelate ReRAM for Next Generation Memory" By Michael Taejoon Park Purdue MSE Preliminary Exam Advisor: Professor Shriram Ramanathan ABSTRACT The traditional semiconductor memory device scaling based on Moore's law is reaching fundamental limits. To overcome this scaling limit, alternative ways have been explored. Among potential candidates, Resistive Random-Access Memory (ReRAM) is one of great interest due to its scalability, low power consumption, and fast programming speed compared with the existing memory technology. ReRAM device uses materials including transition metal oxides that switch the resistance when an external bias is applied. This report summarizes the classification of ReRAM device based on resistive switching characteristics and the underlying mechanisms. Following that, perovskite rare-earth nickelates (RNiO3) as a promising candidate for ReRAM device are reviewed. These materials undergo distinctive metal-insulator phase transition caused by charge disproportionation when temperature decreases. In addition, electron doping through hydrogenation induces a more dramatic phase transition of the same nickelate system which give rise to resistance change by several orders of magnitude. The multi-level resistance states of hydrogen doped RNiO3 could be modulated by electric fields and it provides the potential for emerging memories. Date: Tuesday, December 10, 2019 Time: 9:00 A.M. Place: ARMS 1021

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Seminar Reminder for Ryan Szeto's Preliminary Exam. Seminar Tuesday, Dec. 10, at 9:30 a.m., in ARMS B071. "Investigation of Particle Properties on the Effect of Yield Stress of a Biomass Slurry"
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Investigation of Particle Properties on the Effect of Yield Stress of a Biomass Slurry" By Ryan Szeto Purdue MSE Preliminary Exam Advisors: Professor John A. Howarter and Kendra A. Erk ABSTRACT Corn stover is a lignocellulosic feedstock material that can be used for bioethanol production and alleviates problems with current first-generation biofuels. Despite the great promise of corn stover for biofuel conversion, it is hindered by its recalcitrant nature and high yield stress which is the stress necessary for flow to occur. Incorporating enzymes or dilute acid pretreatment is known to decrease the yield stress and viscosity of the system and increase pumpability. Though it is known that the value of yield stress decreases with processing, its effects on particle properties is poorly understood for corn stover particles. It is proposed that the critical parameters controlling yield stress are dependent on a maximum packing fraction that can change depending on particle shape and size distribution. The impact of aspect ratio, modulus, and roughness are explored for the effect on the value of yield stress. Characterization of these properties will give better insight and understanding of how corn stover particles are modified as a result of processing. Date: Tuesday, December 10, 2019 Time: 9:30 A.M. Place: ARMS B071 School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2200 West Lafayette, IN 47907 765-494-4105 [PU150]

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Seminar Notice for Shukai Yao's Preliminary Exam. Wednesday, Dec. 11, at 8:30 a.m., in ARMS B071. "Quaternary Cu2ZnSn(S, Se)4 Absorber Materials for Photovoltaic Applications"
by Son, Rosemary E 09 Dec '19

09 Dec '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Quaternary Cu2ZnSn(S,Se)4 Absorber Materials for Photovoltaic Applications" By Shukai Yao Purdue MSE Preliminary Exam Advisor: Professor Peilin Liao ABSTRACT Cu2ZnSn(S,Se)4 (CZTSSe) has drawn wide interest in the photovoltaic (PV) community for the last decade as the material components are environmental friendly and abundant on earth, and it has tunability in terms of band gap ranging from 1.0 to 1.5 eV. However, the CZTSSe-based solar cell needs to be improved with respect to energy conversion efficiency (~12%). The inherent elements complexity of quaternary CZTSSe system has raised difficulties in fabricating samples with a high quality. The underlying origin of the difficulties is manifested by two main factors: (i) secondary phases and (ii) point defects. Suppressing their formation will decrease the band alignment fluctuations and the carrier recombination, enhancing the PV performance. Combining the current experimental and computational studies, this review discussed the crystal structure, electronic structure, secondary phases and points defects of CZTSSe, exploring the possible future work on optimizing this PV material. Date: Wednesday, December 11, 2019 Time: 8:30 A.M. Place: ARMS B071

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