November 2021 - Msepostdoc-list

Preliminary Exam Seminar, Thursday, December 9, 9 AM
by Morgan, Yuan-Yu Karen 23 Nov '21

23 Nov '21

Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "Reliability of Recycled Carbon Fiber Reinforced Polymers (rCFRPs) for Sustainable High-Volume Composites" By Morgan Chamberlain Purdue MSE Preliminary Exam Advisor: Professor Jan-Anders Mansson ABSTRACT The high performance and lightweighting advantages of carbon fiber reinforced polymer composites (CFRPs) have become integral within industries such as aerospace, automotive, and sporting goods. However, the growing demand for CFRPs is met with an equally pressing need for sustainable alternatives to the harsh environmental impact that virgin carbon fiber (vCF) manufacturing entails. Additionally, the upcoming end of service life for thousands of aircraft that were manufactured at the forefront of CFRP technology will provide an additional 196,000 tons of carbon fiber waste by 2025, compared to the average 94,000 tons that is already landfilled annually. Hence there is a considerable need to bring recycled carbon fiber reinforced polymers (rCFRPs) into high-volume composites manufacturing as a sustainable alternative to landfill disposal of CFRP waste. This review analyzes the development of carbon fiber recycling technologies, as well as the more recent progress in manufacturing with the recycled material. Challenges are presented that currently hinder the scalability of rCFRPs at high volumes, including fiber surface defects and variability in length retention. Despite the difficulties that these complexities introduce, recycled carbon fiber (rCF) has shown to have excellent retention of mechanical properties, conditional on the optimization of the recycling process. Hence additional research is needed to improve rCFRP processing and assess the reliability of rCFRP structures. The final portion of this work analyzes how the Weibull distribution function can address these gaps by providing a statistical analysis of the mechanical reliability of recycled materials. In this context, understanding the complexity of the current state of recycled carbon fiber, and the difficulties in manufacturability that come with its many forms, is paramount in advancing processing technologies and broadening applications of rCFRPs. Date: Thursday, December 9, 2021 Time: 9:00 AM Place: Webex--https://purdue.webex.com/meet/jmansson Yuan-Yu Karen Morgan,Ph.D. Academic Advisor-Graduate Program School of Materials Engineering Neil Armstrong Hall of Engineering, Room 2217 765-494-4103 ymorgan(a)purdue.edu<mailto:ymorgan@purdue.edu>

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Preliminary Exam Seminar, December 6, Monday, 9:30 AM
by Morgan, Yuan-Yu Karen 22 Nov '21

22 Nov '21

Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "Polymer Infiltration and Pyrolysis Processing of Carbon/Carbon Composites" By Edwin Romero Purdue MSE Preliminary Exam Advisor: Professor Rodney Trice ABSTRACT The low density and high thermostability of bulk carbon make carbon fiber-reinforced carbon matrix composites a good candidate for hypersonic applications. To obtain a pure carbon matrix, a polymer matrix composite is thermally decomposed in an oxygen-free atmosphere, resulting in weight loss and a porous matrix structure. The thermomechanical properties of the porous composite can be improved using polymer infiltration and pyrolysis (PIP) processing, where infiltration and conversion of a secondary polymer causes a carbon build-up on pore walls. This simultaneously decreases the total pore volume and increases the carbon matrix density, but since a portion of the secondary polymer is gasified, some residual porosity is left behind. As a result, several cycles of PIP are needed to obtain bulk densities >90%. This review focuses on some aspects of infiltration for carbon/carbon composites that have been used to reduce densification cycles. Date: December 6, 2021 Time: 9:30 AM Place: https://purdue.webex.com/meet/rtrice Yuan-Yu Karen Morgan,Ph.D. Academic Advisor-Graduate Program School of Materials Engineering Neil Armstrong Hall of Engineering, Room 2217 765-494-4103 ymorgan(a)purdue.edu<mailto:ymorgan@purdue.edu>

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Fw: Freiser Lecture, Tuesday, Nov 30, 2021
by Son, Rosemary E 22 Nov '21

22 Nov '21

________________________________ From: Hanna, Thomas J <hanna9(a)purdue.edu> Sent: Monday, November 22, 2021 10:15 AM To: Mechanical Engineering Graduate Office <megradoffice(a)purdue.edu>; Elwell, Cathy L <celwell(a)purdue.edu>; Golden, Matt <goldenm(a)purdue.edu>; Ricksy, Jennifer R <jricksy(a)purdue.edu>; Zimmerman, Nicole K <nzimmerm(a)purdue.edu>; Son, Rosemary E <son39(a)purdue.edu>; Johnson, Beverly J <bevjohnson(a)purdue.edu>; Delaney, Morgan J <mdelane(a)purdue.edu> Subject: Freiser Lecture, Tuesday, Nov 30, 2021 Please distribute the attached Brochure for the Chemistry Virtual Freiser Lecture, Nov 30, 2021 to your respective areas. Thank you, Tom Hanna Administrative Assistant to: Analytical Division of Chemistry Professors Claridge, Kenttämaa, A. Laskin, J. Laskin, McLuckey, Simpson, Wirth, C. Zhang Organic Division of Chemistry Professors Axelrod, Chmielewski, Lipton, Mao, Mei, Sintim Department of Chemistry BRWN 5171A Purdue University 560 Oval Drive West Lafayette, IN 47907-2084 hanna9(a)purdue.edu<mailto:hanna9@purdue.edu> 765-494-5267

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Reminder: Final Exam Seminar of John Obamedo, Nov. 22, Monday at 2 pm
by Morgan, Yuan-Yu Karen 22 Nov '21

22 Nov '21

Reminder: MATERIALS ENGINEERING SEMINAR "Compositional Effect on Low-Temperature Transient Liquid Phase Sintering of Tin Indium Solder Paste" By John Obamedo Purdue MSE M.S. Final Exam Advisors: Professor Carol Handwerker and Professor John Blendell ABSTRACT Transient liquid phase sintering (TLPS) technologies are potential low-temperature solders for sustainable replacements of lead-based solders and high-temperature lead-free solders. Compared to solid-state sintering and lead-free solders, TLPS uses lower temperatures and is, thus, suitable for assembling temperature-sensitive components. TLPS is a non-equilibrium process and determining the kinetics is critical to the estimation of processing times needed for good joining. The tin-indium (Sn-In) system with a eutectic temperature of 119°C is being considered as the basis for a TLPS system when combined with tin. Most models of TLPS include interdiffusion, dissolution, isothermal solidification, and homogenization and are based on simple binary alloys without intermediate phases. The Sn-In system has two intermediate phases and thus the reaction kinetics require additional terms in the modeling. Differential Scanning Calorimetry (DSC) has been used to measure the response of Sn-In alloys during the transient liquid phase reaction. Preparation of tin indium alloys for microstructural analysis is challenging due to their very low hardness. This study uses freeze-fracturing of the tin indium alloys to obtain sections for microstructural analysis. The combination of DSC and microstructure analysis provides information on the reaction kinetics. It was observed that the solid/liquid reaction does not proceed as quickly as desired, that is, substantial liquid remains after annealing even though the overall composition is in the single-phase region in the phase diagram. Date: Monday, Nov 22, 2021 Time: 2:00 P.M. Place: HAMP 2101

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Rescheduled: Final Exam Seminar Monday, Nov. 22, 2021, 9:30 AM at ARMS 1028
by Morgan, Yuan-Yu Karen 21 Nov '21

21 Nov '21

Dear All, This seminar has been rescheduled to November 22, Next Monday, at 9:30 am at ARMS 1028 ________________________________ From: Morgan, Yuan-Yu Karen Sent: Wednesday, November 10, 2021 1:19 PM To: msegradstudent-list(a)ecn.purdue.edu <msegradstudent-list(a)ecn.purdue.edu>; msefaculty-list(a)ecn.purdue.edu <msefaculty-list(a)ecn.purdue.edu>; msepostdoc-list(a)ecn.purdue.edu <msepostdoc-list(a)ecn.purdue.edu> Cc: Ku Blanco, Aury Y <akublanc(a)purdue.edu> Subject: Final Exam Seminar Friday, December 3, 2021, 3:30 PM at ARMS 1103 Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "EXPLORING THE TUNABILITY OF MARTENSITIC TRANSFORMATION IN SHAPE MEMORY ALLOYS VIA COHERENT SECOND PHASE" By Shivam Tripathi Purdue MSE Ph.D. Final Exam Advisors: Professor Alejandro Strachan and Professor Michael Titus ABSTRACT Shape memory alloys (SMAs) belong to an important class of active materials. Beyond shape memory, these alloys exhibit super-elasticity and pseudo-plasticity, all originating from a reversible phase transformation from a high-temperature austenitic phase to a low temperature martensitic phase. Their unique thermo-mechanical properties make these SMAS desirable for a wide range of applications in automobiles, robotics, aerospace, construction, and medicine. Only a fraction of the known metallic alloys exhibits martensitic transformations, and a relatively small subset exhibits shape memory. Given this limited pool of SMAs, tunability of this martensitic transformation and, hence, thermo-mechanical properties is a way to move forward for effectively designing the next-generation SMAs for specific applications. The modification in composition has always been at the heart of designing new SMAs for future applications. However, a relatively recent discovery of incorporating a second non-transforming phase in base martensitic materials to tune martensitic transformation to achieve unprecedented thermo-mechanical properties has shown great promise. The objective of this work is to utilize the second phase to provide design guidelines for next-generation SMAs and to understand the detailed physics behind the experimentally observed unprecedented thermo-mechanical properties in SMAs as a result of the incorporation of coherent second phases. We first investigate Mg-Sc shape memory alloys that are attractive for a wide range of applications due to their low density. Unfortunately, the use of these alloys is hindered by a low martensitic transformation temperature (173 K). We observe from first-principles calculations that epitaxial strains arising from appropriate substrate or coherent second phase selection increase the martensitic transformation and operational temperature to room temperature. Next, we develop a novel approach to induce martensitic transformation in composite systems of two non-transforming materials. While we demonstrate this approach for the technologically relevant ultra-lightweight Mg/MgLi superlattices, however, our approach is general and will open a wide material space for the discovery and design of next-generation SMAs. Finally, to bridge the gap between computationally studied single-crystalline materials and experimentally studied polycrystalline systems, we characterize the role of nanoscale precipitates on temperature- and stress-induced martensitic phase transformation in nanocrystalline Ni63Al37 SMAs using multi-million-atoms molecular dynamics simulations. Simulations provide the understanding of underlying atomistic mechanisms of experimentally observed unprecedented thermo-mechanical properties and the guidelines to design low-fatigue ultra-fine grain shape memory alloys. As a result of the exploration of novel thermomechanical properties in SMAs via coherent second phases, we also published a software package to discover coherent precipitates within a base multi-component system by coupling high-throughput equilibrium thermodynamics calculations with strain-based lattice matching. Date: Monday, November 22, 2021 Time: 9:30 A.M. Place: ARMS 1028 Yuan-Yu Karen Morgan,Ph.D. Academic Advisor-Graduate Program School of Materials Engineering Neil Armstrong Hall of Engineering, Room 2217 765-494-4103 ymorgan(a)purdue.edu<mailto:ymorgan@purdue.edu>

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REMINDER: Final Exam Seminar, Monday, Nov. 22, at 1:30 pm at HAMP 1266
by Morgan, Yuan-Yu Karen 19 Nov '21

19 Nov '21

From: Msegradstudent-list <msegradstudent-list-bounces(a)ecn.purdue.edu> On Behalf Of Morgan, Yuan-Yu Karen Sent: Monday, November 8, 2021 4:54 PM To: msegradstudent-list(a)ecn.purdue.edu; msefaculty-list(a)ecn.purdue.edu; msepostdoc-list(a)ecn.purdue.edu Cc: Ku Blanco, Aury Y <akublanc(a)purdue.edu> Subject: [msegradstudent-list] Final Exam Seminar, Monday, Nov. 22, at 1:30 pm at HAMP 1266 Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "Design and Processing of NiCo-based Superalloys for the Study of Solute Segregation at Planar Defects During High Temperature Deformation" By Sae Matsunaga Purdue MSE Ph.D. Final Exam Advisors: Professor Michael Titus ABSTRACT Ni-based superalloys have been widely used for high temperature applications such as turbine blades for jet propulsion and power plants due to their excellent creep, fatigue, and corrosion resistance. But as the demand for higher temperature capability and strength increases, there remains a need to better understand high temperature deformation mechanisms and improve and strengthen superalloys at these elevated temperatures. Recently, a correlation has been observed between solute segregation at planar defects (stacking faults, antiphase boundaries, etc) and enhanced high temperature creep properties - known colloquially as phase transformation strengthening. Experimentally, regardless of alloy composition, strong Co segregation at planar defects along with Cr has been observed. In addition, it has been suggested by density functional theory work that Co would promote Cr concentration at stacking faults by forming strong Cr-Co bonds. Based on these findings, it was hypothesized the presence of Co provides a significant thermodynamic driving force for segregation to planar defects. In order to further investigate the correlation between solute segregation and deformation mechanisms the fabrication of a planar front single crystal Ni-based superalloy and its microstructure, alloy composition, and microhardness properties of the as-zone melted and solution heat treated states were investigated and compared to the directionally-solidified state to study the effect of microsegregation on these alloy characteristics. Next, new Co-containing, Cr-free alloys are designed to optimize gamma-gamma' volume fraction, size, and morphology to mimick microstructures observed in single crystal superalloys. The general alloy design strategy and approach are outlined, and the composition, microstructure, phase transformation temperatures, and mechanical properties of new Cr-free and Co-containing alloys are reported. A new set of Cr-free alloys have thus been designed, with modifications of Nb, Ta, and Ti additions ranging from 3 to 7 at.% to investigate the role of these elements on the phase transformation strengthening mechanism at elevated temperatures. Date: Monday, November 22, 2021 Time: 1:30 P.M. Place: HAMP 1266 or Join from the meeting link https://purdue.webex.com/purdue/j.php?MTID=mf23fce9475ea4d01fefa71ab1edf8013 PURDUE MSE [cid:image004.png@01D7DD69.40879190]

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Preliminary Exam Seminar Friday, Dec 3, 9:30 AM
by Morgan, Yuan-Yu Karen 19 Nov '21

19 Nov '21

Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "Modeling of the Growth of Self-assembled Thin Film with Pillar-in-matrix Configuration" By Ahmad Ahmad Purdue MSE Preliminary Exam Advisor: Professor Anter El-Azab ABSTRACT The interesting physical and chemical properties of self-assembled oxide-metal thin films with pillar-in-matrix configurations, known as vertically aligned nanocomposite (VAN), have received a great deal of attention lately. The growth and morphology evolution processes of such films are so complicated that our current understanding of them is still limited. Current research has suggested that, on a thermodynamic basis, the ordering and evolution of the embedded phase configuration in the matrix can be described by in terms of the lattice-mismatch elastic strain and the interfacial energy. From a self-assembly point of view, however, adatom diffusion on the surface, binding energies, and elastic strain influence the clustering, nucleation, and growth of phases. The Kinetic Monte Carlo (KMC) method and the phase field framework capture these events at the atomic and mesoscopic (continuum) sales, respectively. From an experimental point of view, the growth of VAN systems can be affected by the physical and chemical parameters in the pulsed laser deposition technique. There are several reports in the literature describing how such parameters may be incorporated as boundary conditions into the KMC and phase field frameworks to predict the morphological evolution of VAN the systems. In this talk, I will review the use of KMC and phase field methods and how they can be utilized in simulating the growth of multiphase self-assembled nanostructure films. Date: Friday, Dec 3, 2021 Time: 9:30 AM WebEx: https://purdue.webex.com/meet/aelazab | 641105180 Yuan-Yu Karen Morgan,Ph.D. Academic Advisor-Graduate Program School of Materials Engineering Neil Armstrong Hall of Engineering, Room 2217 765-494-4103 ymorgan(a)purdue.edu<mailto:ymorgan@purdue.edu>

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Final Defense Seminar, Friday, December 3, at 10 AM by Webex
by Morgan, Yuan-Yu Karen 19 Nov '21

19 Nov '21

Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR “Preferential Microstructural Pathways of Strain Localization within Nickel and Titanium Alloys” By John Rotella Purdue MSE Final Defense Exam Advisors: Professor Michael Sangid and Professor Rodney Trice ABSTRACT Modern structural materials utilize tailored microstructures to retain peak performance within the most volatile operating conditions. Features such as grain size, grain boundary (GB) character and morphology and secondary phases are just a few of the tunable parameters. By tailoring these types of microstructural features, the deformation behavior of the material is also altered. The localization of plastic strain is directly correlated to material failure. Thus, a systematic approach was utilized to understand the effect of microstructural features on the localization of plastic deformation utilizing digital image correlation (DIC). First, at the macroscopic scale, strain accumulation is known to form parallel to the plane of maximum shear stress. The local deviations in the deformation pathways at the meso-scale are investigated relative to the plane of maximum shear stress. The deviations in the deformation pathways are observed to be a function of the accumulated local plastic strain magnitude and the grain size. Next, strains characterized via DIC were used to calculate a value of incremental slip on the active slip systems and identify cases of slip transmission. The incremental slip was calculated based on a Taylor-Bishop-Hill algorithm, which determined a qualitative assessment of deformation on a given slip system, by satisfying compatibility and identifying the stress state by the principle of virtual work. Inter-connected slip bands, between neighboring grains, were shown to accumulate more incremental slip (and associated strain) compared with slip bands confined to a single grain, where slip transmission did not occur. These results rationalize the role of grain clusters leading to intense strain accumulation and thus serving as potential sites for fatigue crack initiation. Lastly, at GB interfaces, the effect of GB morphology (planar or serrated) on the cavitation behavior was studied during elevated temperature dwell-fatigue at 700 °C. The resulting γ′ precipitate structures were characterized near GBs and within grains. Along serrated GBs coarsened and elongated γ′ precipitates formed and consequently created adjacent regions that were denuded of γ′ precipitates. Cyclic dwell-fatigue experiments were performed at low and high stress amplitudes to vary the amount of imparted strain on the specimens. Additionally, the regions denuded of the γ′ precipitates were observed to localize strain and to be initial sites of cavitation. These results present a quantitative strain analysis between two GB morphologies, which provides the micromechanical rationale to assess the increased proclivity for serrated GBs to form cavities. PURDUE MSE [cid:image002.png@01D7DD39.878D2E90] Date: Friday, December 3, 2021 Time: 10:00 AM WebEx: https://purdue.webex.com/join/msangid

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REMINDER: Final Exam Seminar Monday, November 22, 2021, 9 AM, HAMP 2118
by Morgan, Yuan-Yu Karen 19 Nov '21

19 Nov '21

From: Msegradstudent-list <msegradstudent-list-bounces(a)ecn.purdue.edu> On Behalf Of Morgan, Yuan-Yu Karen Sent: Friday, October 29, 2021 9:41 AM To: msegradstudent-list(a)ecn.purdue.edu; msefaculty-list(a)ecn.purdue.edu; msepostdoc-list(a)ecn.purdue.edu Cc: Ku Blanco, Aury Y <akublanc(a)purdue.edu> Subject: [msegradstudent-list] Final Exam Seminar Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "Phase Transformations in Multicomponent Systems for Solder Joint Reliability" By Alyssa Yaeger Purdue MSE Ph.D. Final Exam Advisors: Professor Carol Handwerker and Professor John Blendell ABSTRACT Solder joints serve as the physical and electrical connection between surface mounted components and circuit boards, and are expected to maintain that connection under stress. Shear stresses due to coefficient of thermal expansion (CTE) mismatch between component and circuit board are common during use, and can lead to fracture of the solder joint. The cracks begin near the solder-substrate interface and propagate through the joint, either through the bulk of the solder or along the interfaces of brittle phases. Therefore, the morphology of the interfacial intermetallic compounds (IMCs) can influence the crack path and whether the failure is ductile or brittle, and thus will determine the lifetime and reliability of the solder joint. Gold embrittlement has been a soldering issue for decades, although it is a broad category which indicates brittle failure due to the presence of gold, typically forming AuSn4. Mitigation of this has included the reduction of Au in the solder joint and the introduction of Cu to destabilize AuSn4-type intermetallics with the formation of (Cu,Ni,Au)6Sn5. A limit of 3wt% Au per solder joint attempted to mitigate this issue, but the methods of gold removal are not precise, and 3% is not a hard limit below which gold embrittlement does not occur. Nickel is able to substitute for Au in AuSn4, forming (Au,Ni)Sn4 in higher volumes at lower gold concentrations, making the establishment of a limit for Au in the joint more difficult. Two methods of establishing these limits are presented in this thesis: isothermal annealing, and thermal cycling. Microstructures evolve over time, even during periods of storage prior to use. Isothermal annealing above storage temperature and below the solidus promotes faster diffusion than seen in practice, due to the temperature dependence of solid state diffusion. This is also known as accelerated aging, as the time and temperature during annealing can be correlated to a different time and temperature during storage. Isothermal annealing allows potential issues, such as gold embrittlement, to be identified more quickly and prior to production, and can give an estimate of product lifetime. For Au-containing solder, Au from the bulk diffuses to the Ni interface to form (Au,Ni)Sn4 during annealing, which causes brittle failure when it forms a thick, continuous layer. Thermal cycling is another method of accelerated testing which can determine the limits of gold embrittlement. Solder joints undergo thermal cycling during product use, and this method increases the cycle frequency to induce earlier failure. This failure is determined by an increase in electrical resistance across solder joints. Failed solder joints can then be cross sectioned to examine the microstructure and crack path to determine cause of failure. Leadless ceramic chip carriers are stiff components with a low standoff height which tends to concentrate thermal expansion mismatch induced stresses in the solder and have thick Au coating, which together make them a good candidate for studies of gold embrittlement. In this thesis, it was determined that these solder joints failed in a ductile manner, determined more by the component characteristics and not as a result of gold embrittlement. A potential mitigation method for gold embrittlement in eutectic Sn-Pb solder joints is also presented in this thesis. Because one cause of gold embrittlement includes the thick, continuous layer of (Au,Ni)Sn4,it has been proposed that breakup of this layer can increase ductility and solder joint lifetime. This can be accomplished with a secondary reflow, or melting, of the solder, using the high solubility of Au in molten solder to destabilize the (Au,Ni)Sn4 and return the solder joint to a more ductile microstructure. The thermodynamics of and mechanisms leading to the destabilization of (Au,Ni)Sn4 are quantified as a function of Au concentration in the solder. The relationship between the solder compositions and microstructure, including interfacial intermetallics, and the fracture behavior of the resulting joints provides insight into the appropriate limits of Au in Sn-Pb solder joints to reduce Au embrittlement. . Date: Monday, November 22, 2021 Time: 9:00 A.M. Place: HAMP 2118

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REMINDER: Preliminary Exam Seminar, Monday, Nov 22 at 9 AM by Webex
by Morgan, Yuan-Yu Karen 19 Nov '21

19 Nov '21

From: Msegradstudent-list <msegradstudent-list-bounces(a)ecn.purdue.edu> On Behalf Of Morgan, Yuan-Yu Karen Sent: Monday, November 8, 2021 9:41 AM To: msegradstudent-list(a)ecn.purdue.edu; msefaculty-list(a)ecn.purdue.edu; msepostdoc-list(a)ecn.purdue.edu Cc: Ku Blanco, Aury Y <akublanc(a)purdue.edu> Subject: [msegradstudent-list] Preliminary Exam Seminar, Monday, Nov 22 at 9 AM by Webex Please consider attending this seminar: MATERIALS ENGINEERING SEMINAR "Role of Surface Energy on the Growth of Vertically Aligned Nanocomposite Thin Films" By Jiawei Song Purdue MSE Preliminary Exam Advisor: Professor Haiyan Wang ABSTRACT Vertically aligned nanocomposite (VAN) thin films are widely explored due to their ability to couple different functionalities and induce three-dimensional strain. Several material systems have been studied include oxide-oxide, oxide-metal, and nitride-metal systems. Thermodynamic analysis of the nucleation and growth process is needed to understand the growth mechanism of self-assembled VAN structure. Thin film growth is affected by multiple factors, such as surface energy, lattice strain, crystal structure, and composition ratio. This review discusses how surface energy affects the growth of VAN thin films and proposes a design guideline for exploring new material systems. Date: Nov 22, 2021 Time: 9:00 AM WebEx: https://purdue.webex.com/purdue/j.php?MTID=m212b44464e40df23ee6c87a4c9fe62eb

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