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MSE Seminars

 

 

Materials Science & Engineering Seminar

Application of Crystal Plasticity Modeling: Thermal Ratcheting

Dr. Jonathan Nickels

University of Cincinnati
Department of Chemical & Environmental Engineering Email: nickeljo@ucmail.uc.edu

Friday, January 19th, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

The structure and function of biological membranes is far more complex than the classical view of a homogeneous fluid mosaic. Though it has been studied for more than 100 years, the role of lateral organization stemming from its rich compositional diversity a is still being unraveled. Often, the lipid raft hypothesis is invoked to contextualize the observations of lateral heterogeneities in the plane of the membrane. The lipid raft hypothesis suggests that these nanoscopic and transient lateral structures facilitate the organization, assembly and regulation of multi-molecular protein complexes. Provides a compelling rationale for numerous observations relating to complex biological functions such as membrane trafficking, endocytosis, signal transduction, and other processes. There is an unrealized potential to unlock new understanding and therapies to a variety of diseases based on an improved grasp of the structure and biophysical basis of lipid raft formation and properties.

I will discuss recent work establishing a platform for systematic in vitro and in vivo investigations of cell membrane organization; setting the stage to both understand and access the potential of these enigmatic membrane structures. Using both neutron scattering as well as simulation based approaches, we first accessed the bending modulus of the ‘raft’ structures in model lipid mixtures. This result provides fundamental information about the underlying physical mechanisms of raft formation and stability. These observations relied upon neutron ‘contrast matching’ approaches to resolve scattering signals from the co-existing lipid phases. This work lead into current efforts to probe the structure and organization of the cell membrane in a living organism, B. subtilis, by extending these scattering based approaches in combination with a number of innovative genetic and biochemical strategies. Ultimately, we

have been able to isotopically label a living bacterial system to present neutron contrast between the cell membrane and the rest of the cell/extracellular space in order to directly observe the cell membrane of a living organism. This approach has already yielded the first direct in vivo observations of bilayer hydrophobic thickness as well as evidence for the existence of lipid rafts in this organism.

 

 

Mechanical Engineering Graduate Seminar

Laser-material interactions to pave the way for functional materials

Sarah J. Wolff

Advanced Manufacturing Processes Laboratory Department of Mechanical Engineering Northwestern University

Friday, January 19, 2018; 11:15 AM – 12:10 PM; 544 Baldwin Hall

Abstract

Powder-blown and laser-based additive manufacturing processes provide unique opportunities for novel materials design of functional materials with complex component geometries and improved mechanical behavior due to its unprecedented rapid solidification. The nature of the process opens doors to multi-material capability at many length scales. However, the complex physical phenomena that occur during the process leads to uncertainties in structure and mechanical behavior. Research that couples experiments and thermal modeling aims to investigate the relations between the process, thermal history, microstructure and final mechanical behavior of additively manufactured materials. Some of the very first experiments of in-situ high-speed X-ray imaging of the powder deposition process at Argonne National Laboratory illuminate how processing conditions influence the build. Thermal monitoring, structural characterization and mechanical testing show what mechanisms in the process lead to final part properties. Optimal process control requires thorough understanding of these process-structure-property relationships so that the same part could be built by various machines and systems. Future work includes manipulating laser- matter interactions with external magnetic fields, adaptive optics and reheating so that the complex phenomena in the process will not only be isolated and understood, but also used to build new functional materials.

Speaker Biography

Sarah Wolff is finishing up her PhD in mechanical engineering from the Advanced Manufacturing Processes Laboratory with Professors Jian Cao and Kornel Ehmann at Northwestern University. After completing a B.S. degree in environmental engineering at Northwestern and working in the aerospace industry, she transitioned to research sustainable manufacturing systems and later advanced processes. Sarah studies the underlying physics of laser-material interactions in both subtractive and additive processes and their influence on resulting microstructure and mechanical behavior. She is also building an open-architecture hybrid processing rapid prototyping machine in hopes to design new materials.

 

 

Materials Science & Engineering Seminar

Understanding and Controlling the Bond Surface in Manufacturing for Reliable Adhesive Bonding

Dr. Giles Dillingham

CEO and Chief Scientist, BTG Labs Email: gdillingham@btglabs.com

Friday, February 2nd, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

The interactions between a bond surface and an adhesive that determine the strength and reliability of a bonded structure occur in a zone that is perhaps 1 nanometer thick. This seminar provides a comprehensive look at the molecular level characteristics of a bond surface that determine bond performance, how to establish the desired characteristics through surface preparation, and how to quantify them for process development, quality assurance, and failure analysis. We will provide an overview of the basic scientific principles involved in measuring surface composition and surface energy and how these relate to bond performance in manufacturing and repair.

Bio

Giles Dillingham, CEO and Chief Scientist of BTG Labs, has worked in the areas of materials, surfaces, interfaces, and adhesive bonding since receiving his Ph.D. in Materials Science from UC in 1987. BTG Labs, established by Dr. Dillingham in the late 1990’s, performs basic and applied research in surface science, surface treatments and adhesion, and develops instrumentation for development and process control of surface engineering processes. Recent work by BTG Labs is helping pave the way to certifiable adhesively bonded primary aircraft structures. Dr. Dillingham has over 40 publications and patents in the areas of surface treatments, surface energetics, and adhesion.

 

 

Materials Science & Engineering Seminar

Application of Crystal Plasticity Modeling: Thermal Ratcheting

Dr. Christopher A. Calhoun

Engineer, Technical Data Analysis, Inc. Email: ccalhoun@tda-i.com

Friday, February 9th, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

α-Uranium’s orthorhombic crystal structure leads to many unique phenomena. Most interestingly, textured polycrystals exhibit thermal ratcheting, which is defined as the accumulation of permanent deformation through repeated stress-free thermal cycling. The driving force for the ratcheting stems from the anisotropy of the single crystal thermal expansion coefficient of the single crystal, which possesses one direction with a negative CTE. Despite having been reported in the literature in the 1950’s and 60’s, a thorough modeling explanation of ratcheting has not been presented. This talk will present a combined experimental and modeling effort to explain the mechanisms for the thermal ratcheting. A brief overview of plasticity modeling, with a focus on crystal plasticity will be included.

Bio

Dr. Calhoun grew up in Reno, NV, where he discovered that careers can be dedicated to breaking metal and making sense of it. In an effort to pursue that goal, he went to Virginia Tech to obtain a Bachelor’s in Engineering Science and Mechanics, where he worked on fatigue in aircraft aluminum. After that, he went onto obtain a Master’s in Aerospace Engineering from Texas A&M studying thermo-mechanical fatigue of shape memory alloys. In an effort to return to return to Virginia, Chris enrolled obtained a PhD in Materials Science and Engineering at the University of Virginia. There he focused on the polycrystalline plasticity. He went on to work two years at NIST in the Center for Automotive Lightweighting studying plasticity as applied to shaping and forming. Recently, he started at Technical Data Analysis, Inc. working on a variety of projects with a primary focus on metal fatigue in aerospace structures. In his free time, Dr. Calhoun teaches “Introduction to Finite Element Analysis” as an adjunct faculty member in the mechanical engineering department at George Mason University.

 

 

Materials Science & Engineering Seminar

Printed Homes: Additive Manufacturing Reforming Construction Technology

Dr. Seyed Allameh

Professor of Physics, Geology and Engineering Technology Northern Kentucky University
Email: allamehs1@nku.edu

Friday, February 23rd, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

Imagine you draw a house with a desired shape, send it to a printer and it gets printed, not on small prototype one from polymers, rather, a life-size, real home that you can move in! Imagine a home that resists earthquakes and fire so we do not see the collapse of buildings causing human casualties, Imagine construction under hazardous conditions, in cold and hot weather in very short periods of time and at very affordable costs! All these are becoming feasible with the advent of new 3D printing technology associated with advances in construction composites with intricate micro- and macrostructures such as cellular, lattice block, and sandwich structures. Biomimicking, as the new enabling technology and its incorporation in 3D printing of houses written from bioinspired materials will be discussed and its implications on the current construction technology will be elucidated.

Bio

Dr. Seyed Allameh is currently is professor of Physics, Geology and Engineering Technology at Northern Kentucky University. He joined NKU in 2004 after 5 years of research in the areas of MEMS, and advanced materials at Princeton University as research staff scientist. Prior to Princeton, he worked on the synthesis and characterization of electronic ceramics at The Ohio State University as research associate and postdoctoral fellow. He received his PhD in 1993 from OSU in the field of Materials Science and Engineering. For his PhD, he worked on the energy and structure of interphase interfaces

Dr. Allameh has worked on the fabrication and characterization of nano-crystalline materials, microelectromechanical systems (MEMS), thin film bimorphs, biomaterials, and nanostructures with applications in nanotechnology. He has a special interest in surfaces and

interfaces, electron microscopy, nano-crystalline materials, nano-scale and microscale devices, and microtesting systems for mechanical behavior of MEMS and NEMS. He has developed state of the art microtesting systems for evaluation of mechanical behavior of MEMS components. These included tensile, compression, bending, buckling, fatigue and creep tests using laser interferometry and image correlation techniques. At Princeton, he developed a simple method for growing nano-scale structures including nanofins, nanorods, and thin-walled lightweight nanostructures.

Dr. Allameh has authored or co-authored over 80 peer- reviewed journal articles, conference proceedings papers and book chapters. Further, he has given 46 conference presentations including invited talks at various universities and international conferences. He was the guest editor of a special issue of Journal of Materials Science and Engineering. He organizes symposia on Bio materials, Bioinspired materials and biofuels at the ASME international conference and exhibition. He is the recipient of awards and recognitions including the 2017 NKU outstanding research award. His current research is focused on biomimicked composites and micromechanical characterization of MEMS components.

 

 

Materials Science & Engineering Seminar

Understanding the Physical Metallurgy of Ni-Based Alloy Haynes 244

Dr. Jie Song

Research Associate, Colorado School of Mines Email: j.song.thu@gmail.com

Friday, March 2nd , 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

Ni-based superalloys display excellent mechanical properties at high temperatures as well as superior oxidation and corrosion resistance. They are widely used in gas turbines, and chemical plants. In this talk, the morphology and development of precipitate-free zones (PFZs) near grain boundaries (GBs) in low coefficient of thermal expansion (CTE) Ni-15.6Mo-10.2Cr- 2.2W at.% (based on Haynes 244) will be discussed as a function of thermal history and composition using electron microscopy techniques. The formation of wide, continuous PFZs adjacent to GBs can be largely attributed to vacancy depletion in the vicinity of the GBs. The crystallography of grain boundary precipitates has been investigated using transmission electron diffraction. The space group of previously unreported cubic precipitate is Pm3̅m with lattice parameter a=6.42Å.The μ phase that formed during this heat treatment contains a high density of finely spaced (0001) nanotwins, which give rise to pseudo 6/mmm symmetry (instead of 3̅m, expected for the μ phase R3̅m space group) in CBED patterns. In addition, variant selection of intragranular Ni2(Mo,Cr) precipitates will be discussed.

Bio

Jie Song received his Master’s degree in materials science and engineering from the Tsinghua University, in 2009, and PhD degree in Engineering Technology from Purdue University in 2014. He conducted his postdoctoral studies at Colorado School of Mines and Purdue University. Jie Song’s research interests lie in the area of material characterization based on advanced microscopies as well as material processing and properties.

 

 

Department of Chemical and Environmental Engineering Seminar (in conjunction with the Materials Science & Engineering Program)

Nano-Engineered Materials

Dr. Pulickel M. Ajayan

Department of Materials Science and NanoEngineering Rice University, Houston, Texas,

Friday, March 30th, 2018 12:20 - 1:15 pm
Rec Center 3250

Abstract

The past two decades has belonged to truly innovative discoveries in the area of nanotechnology. Although basic science in the area has progressed significantly, there are still challenges related to engineering and integration of nanomaterials into applications and commercial products. This talk will discuss some of the challenges and opportunities in the field, with particular reference to engineered nanomaterials that include carbon nanostructures, two dimensional materials, and several other nanomaterials and hybrids. Our group has made pioneering contributions to this field in relevance to developing these materials for applications such as energy storage and conversion, catalysis, low power devices, coatings and light-weight materials. Several aspects that include synthesis, characterization and modifications will be explored with the objective of achieving functional nanostructures for future technologies. The intrinsic challenges in the area of nano-engineering will be highlighted, particularly for bottom-up creation of nanostructured materials.

Bio

Dr. Pulickel M. Ajayan, the Benjamin M. and Mary Greenwood Anderson Professor of Engineering, is the founding Chair of the Materials Science and NanoEngineering Department in the Brown School of Engineering at Rice University. Prof. Ajayan started out as a metallurgist, and moved quickly into carbon nanotechnology as his major area of focus, with world-leading research into multi- and single-walled carbon nanotubes - their growth in vertical arrays and their uses in composites and other materials - and in graphene and hybrid carbon nanomaterials. Prof. Ajayan has published one book and 600 journal papers with > 130,000 citations and an h-index of 151, based on ISI database. He has received a number of rewards among which including the 2016 Lifetime Achievement Award in Nanotechnology from the Houston Technology Center, 2016 NANOSMAT Prize, Spiers Memorial Award by the Royal Society of Chemistry (UK), Senior Humboldt Prize, MRS medal, and Scientific American 50 recognition. He has been elected as a fellow of the Royal Society of Chemistry (UK) and other academies, as well as serving as visiting and guest faculty positions across the globe.

 

 

 

Materials Science & Engineering Seminar

A Chemical Engineer’s Adventures in the Semiconductor Industry

Dr. George P. Fotou

Principal Engineer, Cabot Microelectronics Email: George_Fotou@cabotcmp.com

Friday, March 30th, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

Chemical Mechanical Planarization (CMP) is a technology not broadly known but a very important step in the fabrication of IC semiconductor devices. A brief introduction of this technology will be provided as well as how it is enabling the miniaturization of the chips that are used in semiconductor devices. Slurries made from highly engineered abrasive particles and designed to operate within very tight performance limits of removal rate, defectivity and uniformity are integral part of CMP. Polishing pads play an equally important role in the CMP process. These are materials based on either thermoplastic or thermoset polyurethane polymers and manufactured by various processes to achieve specific physical characteristics and mechanical properties that are important in the CMP process

A message that I would like to convey with my talk is that transitions from traditional technical fields to “non-traditional” ones can be exciting and rewarding.

Bio

Dr. Fotou earned his doctorate degree from the University of Cincinnati, Department of Chemical Engineering in 1995. After a post-doctoral appointment at the University of New Mexico, he joined Cabot Corporation in 1996. In his 14 year R&D career with Cabot, Dr. Fotou developed, scaled up and commercialized several processes for nanoparticle production and filed several patents. He joined Cabot Microelectronics in 2010 where he is currently a Principal Engineer. For the past 7 years Dr. Fotou developed and commercialized polishing pads for Chemical Mechanical Planarization (CMP) of advanced semiconductor materials. He is currently managing the supply of abrasive particles for the manufacture of CMP slurries.

 

 

Materials Science & Engineering Seminar

Characterizing the Age of Ancient Egyptian Manuscripts through microRaman Spectroscopy

Dr. Sarah Goler

Columbia Nano Initiative, Columbia University, New York Email: sg2175@gmail.com

Friday, March 23rd, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

We have established scientific basis for a new, nondestructive methodology for dating ancient Egyptian papyri based on Raman spectroscopy. Egypt’s dry climate has preserved thousands of handwritten documents which provide insight into ancient cultures, but most of these manuscripts are not dated. Currently, the only scientific method for estimating the date is radiocarbon dating, which is destructive and cannot be used to date the ink separate from the support. In contrast, microRaman spectroscopy, a nondestructive light scattering technique, can distinguish physical and chemical properties of materials. We discovered, for a study of well dated ancient Egyptian papyri covering the date range from 300BCE to 900CE, the Raman spectra (20-40 measurements per manuscript) of black ink all show the spectrum of carbon black characterized by two broad features, the G and D bands indicative of crystalline and amorphous carbon. The G band, 1585cm-1, is a Raman allowed transition arising from the E2g inplane vibration of sp2 bonded carbon. The D band at ~1350cm-1 is a forbidden Raman transition that occurs when the lattice symmetry is broken due to disorder, vacancies, crystalline edges, etc. We observed the spectra exhibit systematic change as a function of manuscript date, unexpected given these papyri span 1,200 years and the fact that each manuscript has a unique provenance, archeological, and storage history. We conclude Egyptian black ink pigments were manufactured using similar processes over this time period. We attribute the systematic changes in Raman spectrum to two concurrent oxidation processes: slow oxidation of crystalline carbon and faster oxidation of amorphous carbon. Oxidative degradation proceeds over time altering the Raman response of the material, providing a direct experimental indicator for manuscript age. This research establishes the basis for a simple, rapid, nondestructive method for dating ancient manuscripts from Egypt as well as the ability to differentiate between modern forgeries and authentic ancient manuscripts. To validate this method we performed a blind study where the scientific team performed the measurements and provided predicted dates without knowing the true dates which were revealed later.

Bio

Sarah Goler completed her undergraduate studies in applied physics at Columbia University's School of Engineering and Applied Science and Mathematics. She went on to complete a PhD in Condensed Matter Physics at the Scuola Normale Superiore di Pisa in Italy where she focused on graphene for hydrogen storage using STM, microRaman and CVD processes. She then continued her studies of carbon while completing a postdoctoral position at Columbia University as a member of the Ancient Ink Laboratory. She won a year-long research scientist fellowship with the Italian Academy at Columbia University in 2014/2015 and won the Dan David Prize for young scholars in 2017.

 

 

Materials Science & Engineering Seminar

Simulating Microstructural Evolution during Metal Additive Manufacturing

Dr. Theron Rodgers

Sandia National Laboratories Email: trodger@sandia.gov

Friday, April 20th, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

With the rapid growth of additive manufacturing, rapid solidification phenomena have become increasingly important in the materials community. Recently, we have introduced a novel Monte Carlo-based method of simulating microstructural evolution during process such as additive manufacturing, welding, and thin film solidification. Here, we will discuss recent work with the model including coupling it to thermal conduction simulations, incorporating crystallographic texture, and using synthetic microstructures in simulations of mechanical behavior.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

 

Materials Science & Engineering Seminar

Closed-Loop Research and Development of Gas Atomization and Selective Laser Melting for Additive Manufacturing of Metallic Alloys

Dr. Yongho Sohn

Professor, Department of Materials Science and Engineering University of Central Florida, Orlando, FL, USA
Email: Yongho.Sohn@ucf.edu

Friday, April 13th, 2018 2:30 pm 3:25 pm Zimmer 413

Abstract

Additive manufacturing of metallic alloys is emerging as a disruptive technology to produce net- shape components with nearly unlimited geometrical complexity and customization. This technology also represents an opportunity to design new and modified alloys that can desensitize inherent process variables and take advantage of thermo-kinetic environments associated with additive manufacturing. In this presentation, in-laboratory, hands-on, closed-loop research capability of gas atomization and selective laser melting for alloy development established at UCF will be introduced. Exploration and optimization of process parameters will be documented for gas atomization (e.g., flow rate, atomizing pressure, melt temperature and orifice temperature) and selective laser melting (e.g., laser power, scanning speed, hatch spacing and slice thickness) using microstructure and mechanical properties. Demonstrative results from commercially available and new/modified Al-, Ni-, and Fe-alloys will be discussed to identify scientific understanding required to mature additive manufacturing technology including solidification, micro-segregation, homogenization, and precipitation via multicomponent phase equilibria and diffusion.

Bio

Dr. Yongho Sohn is a Pegasus Professor of Materials Science and Engineering, and Associate Director for Materials Characterization Facility (MCF) at University of Central Florida. MCF is a FL-state user facility for academics and industry with over $20M in analytical instrumentation and 3 full-time staff engineers. He received his B.S. with honors and M.S. from Worcester Polytechnic Institute, Worcester, MA in mechanical and materials engineering, respectively. He graduated in 1999 with a Ph.D. in materials science and engineering from Purdue University and spent two years as a post-doctoral research scholar at the University of Connecticut. He joined University of Central Florida in 2001 as an assistant professor. His research and teaching interests includes microstructural analysis and control, multicomponent intrinsic and

interdiffusion in multiphase alloys, powder processing and additive manufacturing, thermal barrier coatings and other protective metallic/ceramic coatings, and light-weight metallic alloys and metal-matrix composites. He has published 8 book chapters, over 140 journal papers and 60 proceedings papers. He gave over 400 presentations including 100 invited lectures at conferences around the globe. He is a Fellow of ASM International (FASM), recipient of NSF CAREER Award (2003), Outstanding Materials Engineer Award from Purdue University (2016), UCF’s 2017, 2012 and 2006 research incentive awards, UCF’s 2007 and 2013 teaching incentive award. He is an associate editor for Journal of Phase Equilibria and Diffusion and a member of editorial board for Metallurgical and Materials Transactions. He has supervised to completion, 11 Ph.D. students, 29 M.S. students and 8 post-doctoral scholars, and currently supervises 4 Ph.D. students, 1 research associate, and 4 undergraduate research assistants. Details on his research and teaching activities can be found at http://mse.ucf.edu/sohn.