Graduate Seminar - Spring 2021
A Lecture Series in Materials Science and Engineering
Fridays 12:00-12:50 - Speare 113
Design and Characterization of Nanostructured Titanium Alloys
Yufeng Zheng, Ph.D.
Department of Chemical and Materials Engineering
University of Nevada Reno
In order to reduce the fossil fuel consumption and greenhouse gas emissions, there is a continued demand for new generation lightweight materials for better performance and fuel efficiency in the modern aircraft and automobiles. With the development of the advanced characterization techniques, we are able to obtain a detailed understanding of the nanostructure in materials during processing and service, that provides more reliable experimental database for the computational modeling to expedite the design of novel materials with better performance. This presentation is mainly focused on the application of analytical microscopy to explore the fundamental mechanisms in the development of novel metals and alloys. Several studies about designing advanced titanium alloys for aerospace application via nanostructure engineering utilizing the cutting-edge characterization techniques will be introduced. Novel nanoscale O” phase with ordered orthorhombic structure has been characterized for the first time in the metastable beta titanium, revealing a new nanoscale short range ordering mechanism. Ultra-high strength metastable beta titanium alloys, via the precipitation strengthening through the O” phase assisted alpha precipitation mechanism, have been investigated coupling the atomic resolution aberration-corrected scanning transmission electron microscopy and 3D atom probe tomography. The twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) in the gum-like multifunctional titanium alloys will be discussed, with the focus on the nanostructure in the interior and at the boundary of high-indexed deformation twins.
Dr. Yufeng Zheng is an assistant professor in the Department of Chemical and Materials Engineering at University of Nevada Reno. Yufeng’s research is focusing on the exploration of the processing-structure-property relationships in the metallic materials during advanced manufacturing using multi-scale ex-situ and in-situ characterization techniques. His research interests involve the discovery, synthesis and design of next generation high-performance metallic materials by micro- and nano-structure engineering, especially the lightweight high-performance metallic materials, such as titanium alloys fabricated by additive manufacturing for aerospace, chemical and bio-medical applications. Yufeng has published more than fifty papers in the peer-reviewed journal and international conference proceedings and he has presented his work over twenty times at international conferences. He was named among five finalists for the Aaronson Award for outstanding young researcher at the 2015 International Conference on Solid-Solid Phase Transformation in Inorganic Materials.
Understanding how macroscopic thermomechanical deformation conditions govern metal manufacturability and performance
Forging Industry Educational and Research Foundation Professor Colorado School of Mines Dept. of Metallurgical and Materials Engineering
Metallic alloy processing and service conditions have significant effects on our ability to manufacture metals with desired microstructures and implement those metals in performance critical applications. Accumulative roll bonding (ARB) affords the ability to create fine-grained microstructures with otherwise unobtainable properties, but bulk manufacturability is limited by severe edge cracking that occurs due to the necessary large, single-pass rolling reductions. Here we show that lateral constraint can significantly reduce or eliminate edge cracking and maintains improved thickness homogeneity during ARB of aluminum alloys. This methodology greatly improves sample quality and yield when applied to multiple ARB cycles and is scalable to bulk manufacturing processes. Similarly, quenching and partitioning (Q&P) processing of third-generation advanced high strength steels generates multiphase microstructures containing metastable retained austenite and has produced cost-efficient structural steels with unprecedented performance for automotive structural applications. That performance is most commonly quantified in the laboratory by tensile testing at quasi-static strain rates. Both manufacturing processes such as stamping and in-service deformation due to crash events deviate significantly from the strain state, path, rate, and temperature conditions commonly tested. Thus, tailoring austenite stability is critical for optimizing the forming response and crash performance of quenched and partitioned grades.
Kester Clarke is an assistant professor in the Metallurgical and Materials Engineering Department at Colorado School of Mines and serves as the Forging Industry Education and Research Foundation (FIERF) Professor and holds a joint appointment as a scientist at Pacific Northwest National Laboratory (PNNL). He engages in research on deformation processes in metal alloys with the Center for Advanced Non-Ferrous Structural Alloys and the Advanced Steel Processing and Products Research Center. His research interests include alloy development, material deformation and fabrication processes, and the use of experimental and modeling methods to examine the effect of material processing history and microstructure on mechanical properties and performance. Dr. Clarke holds a B.A. in Psychology from Indiana University, a B.S. in Materials Science and Engineering from Wayne State University, and M.S. and Ph.D. degrees in Metallurgical and Materials Engineering from the Colorado School of Mines. He has worked as a consulting Metallurgical Engineer for Engel Metallurgical and as a Senior Engineer/Research and Development for Caterpillar. He conducted postdoctoral research at Los Alamos National Laboratory, was an R&D scientist/engineer in the Materials Science & Technology: Metallurgy group serving as the technical lead for thermal-mechanical processing of metals and metal component fabrication and is currently a Visiting Scientist at LANL.
Dynamic tensile failure of rolled magnesium: the role of texture and second-phase particles
New Mexico Tech
The US Army has continual interest in the development of lightweight armor materials for soldier protection. To this end, magnesium alloys are being evaluated as potential materials for vehicle armor. Dynamic tension experiments have been conducted to investigate the direction-dependent deformation and failure behavior of magnesium alloy AZ31B after hot rolling. Specimens were subjected to uniaxial tension along several orientations in the Normal--Rolling plane of the parent plate. High-speed imaging is utilized to capture the deformation behavior on the microseconds time scale, allowing for the localization behavior at the onset of failure to be investigated. Failure surface morphology was measured to characterize the direction-dependent failure behavior of this material. The experimental results indicate that second phase particles present in the material serve as failure initiation sites. The distribution and orientation of these particles were characterized using micro CT scanning allowing for their incorporation into numerical simulations as discrete particles. Results of three-dimensional polycrystal plasticity simulations with and without realistic precipitates are compared to the experimental results to understand the relative effects of plastic anisotropy and second phase particles on the failure behavior of this material.
Jamie Kimberley received his B.S. in Mechanical Engineering from the State University of New York at Binghamton. Thereafter he attended the University of Illinois at Urbana–Champaign, receiving his M.S. in Theoretical & Applied Mechanics and his Ph.D. in Aerospace Engineering. Upon completion of his Doctoral degree he joined the Department of Mechanical Engineering at Johns Hopkins University as a postdoctoral fellow. He joined the Department of Mechanical Engineering at New Mexico Tech in 2012 and is currently an Associate Professor.
His research group, the Dynamic Deformation and Failure Lab, focuses on the experimental characterization of materials/structures subjected to high rate loading and the development of physics-based of models based on the observed behavior. Current topics of interest include dynamic problems with coupled response (reactive materials, mechanoluminescence), shock wave interactions, and materials for improved armor performance.
Nucleation mechanism in Lightweight structural alloys
New Mexico Tech
Nucleation process has a profound influence on the formation and evolution of alloy microstructure from liquid and solid states. Here, taking Magnesium and Aluminum alloys as examples, I will present some recent results on the investigation of nucleation mechanisms. Consequently, the presentation will be divided into two parts.
β1 is a key strengthening precipitate phase in Mg-Nd-based alloys, because it is known to improve high- temperature creep resistance. Using density functional theory-based first principles calculations, we have examined the structure and local environment of β1 nucleus that forms within hcp-Mg lattice. We learn that β1 will initially form within hcp-Mg as smaller structural templates rather than the larger equilibrium structure. In essence, these templates are the “genetic imprint” of the equilibrium structure that contains only a portion of larger β1 crystal structure, while retaining the stoichiometry and nominal symmetry of β1. Broadly, our DFT results provide crucial insights into intermetallic phase nucleation, whose lattice parameters differ significantly from the host lattice.
Structural mechanisms causing local coordination changes during crystallization and vitrification in dilute face- centered-cubic (FCC) alloys were investigated using model Al-Sm, which also serves as prototype for lightweight Al-rare earth (RE) structural alloys. Molecular dynamics simulations were performed to study the solidification behavior of Al-1at.%Sm and Al-5at.%Sm. Two structural features were identified from these simulations, which are related to the molten state and the glass transition (Tg). In case of Al-1at.%Sm, we learn that, near the melting point, liquid phase manifested pockets of unique transitional structures comprising triangular arrangements in near-parallel layers that encapsulated a FCC-HCP coordinated core. Near the Tg Al-5at.%Sm achieves additional local ordering via the formation of inter-penetrating icosahedral frameworks.
Bimetallic Plasmonic Nanomaterials with Tunable Optical Properties
New Mexico Tech
The interests of our research group evolve around the development of optically active nanostructures such as plasmonic nanoparticles for different applications, ranging from the detection of biomolecules to solar energy conversion. Plasmonic nanoparticles can strongly enhance local electromagnetic field; and their ability to concentrate light in the nanoscale have found a broad range of applications. Presently, our research group focus on two specific areas: (1) Development of efficient photothermal materials which can convert light into heat for different applications such as solar enhanced water evaporation and photothermal biomedical devices. (1) Development of plasmonic materials to efficiently concentrate light in the nanoscale to drive energy-expensive reactions. We are studying refractory plasmonic nanomaterials and bimetallic nanoparticles for efficient conversion of light into other forms of energies such as thermal, chemical, and electrical energy. In this talk, I will particularly focus on our efforts to develop bimetallic plasmonic nanoparticles. Our work demonstrated that both light absorption properties as well as the relaxation dynamics of bimetallic plasmonic nanoparticles can be tuned by tuning their composition. The possibility to control and tune the above properties of bimetallic plasmonic materials assumes a paramount relevance in the development of different applications such as plasmon enhanced catalysis as well as biosensing.
- Sim S, Beierle A; Mantos P; McCrory S; Prasankumar R.P. and Chowdhury S; "Ultrafast relaxation dynamics in bimetallic plasmonic catalysts". Nanoscale.,2020, 12, 10284-10291.
- Bhethanabotla, V. R. and Chowdhury, S. "Alloy nanoparticles for metal enhanced luminescence." U.S. PatentNo. 9,005,890 (2015)
- Chowdhury, S.; Bhethanabotla, V. R. and Sen, R. “Silver-copper alloy nanoparticles for metal enhanced luminescence.” Appl. Phys. Lett. 95 131115-1-3 (2009).
Atomistic modeling of phonon transport
Laura de Sousa Oliveira
University of Wyoming
The ability to control and manipulate heat goes hand in hand with human progress. This was the case in pre-history—when we mastered fire for cooking, heating and defense—and it continues to be true today. As devices get smaller and our ability to nanostructure materials improves, to predict and control heat transport in next-generation materials and devices, it becomes essential to develop an atomistic-level understanding of thermal transport. My research to date has focused on thermal transport at the atomistic scale, including classical molecular dynamics, ab initio approaches and heuristic models in a variety of materials. In this talk, I will discuss thermal transport in three types of bulk materials with a wide array of functionalities, applications and transport properties: graphite, nanoporous silicon, and metal–organic frameworks. Applications for these materials range from nuclear engineering, as is the case with graphite, to energy generation, and storage, among others. Classical molecular dynamics is especially useful to evaluate thermal transport in defect-laden structures. For instance, to advance our knowledge of the evolution of the microstructure of graphite while in service in a graphite-moderated nuclear reactor, I investigate how various point defects and concentrations thereof affect thermal transport. While a high thermal conductivity is ideal for a nuclear moderator, thermoelectric applications require very low thermal conductivities. Thermoelectric devices, which convert temperature differences into an electrical current and vice-versa, are a promising technology for waste heat recovery— approximately two-thirds of all the energy that is generated is lost as waste heat! The introduction of nanopores drastically reduces a material’s thermal conductivity, but there is not yet a clear understanding of why that is. Using large-scale molecular dynamics simulations (of hundreds of thousands of atoms), I study the effect of pore configuration on thermal transport to identify the most important mechanisms for thermal conductivity reduction in porous materials. Finally, we take a brief look at thermal transport in metal–organic frameworks (MOFs). MOFs are highly modular and have large surface areas and are therefore promising for numerous applications, including hydrogen storage and carbon sequestration. A simple geometric model of thermal conductivity is proposed as a heuristic for the quick evaluation of thermal transport in flexible MOFs, and a quantum-based approach is implemented to explore deviations from the heuristic, resulting in the discovery of emergent rattler modes and heat-focusing properties that can be switched on and off.
Making Ceramics Great Again:
Solid State Batteries by DAD
New Mexico Tech
Most all technologies, to some degree, rely on the invention, development and/or integration of advanced ceramics. Advanced batteries are no exception, whether the sodium-sulfur battery, ubiquitous lithium-ion battery (LIB), or the future all-solid-state-battery (ASSB). In fact, other than the lithium foil, the remainder of critical component parts of the ASSB cell (solid electrolyte, cathode, and current collector) are ceramic. The solid state construction is expected to dramatically increase volumetric efficiency, energy density, lifetime and safety compared to state-of-the-art LIBs. Materials challenges for the ASSB include maximizing and controlling mixed ionic-electronic conductivity within the several components, interface stability and mechanical stability. The manufacturing challenges, as in any new energy technology, lie in cost and scaling to mass production. It is easy to imagine the manufacturing of ASSB beginning with solid state ceramic powder preparation, then suspension, layer forming (i.e. tape casting), lamination and compaction, and finally sintering. Though these are well-established ceramic fabrication steps, they have some inherent drawbacks with regard to the demands of the ASSB.
There exists a new and developing additive manufacturing (AM) technology that may be ideal for the building of ASSB cells called (Dry) Aerosol Deposition, DAD. It is a kinetic spray process wherein ceramic particles are accelerated to high velocity, impact a substrate, and fracture into nanoparticles, which re-bond and densify with repeated impacts. The resulting full-density, nanostructure is expected to be ideal for battery component applications. DAD is scalable, and may prove to be economically viable.
Prof. Fuierer will give some background on the topic of solid state batteries, and present some early DAD work done by his group with battery ceramics.
Schnell et.al., J. Power Sources 382 (2018)
Hanft et.al., J. Power Sources 361 (2017)
Hanft et. al., J. Ceramics Science & Technology 6 (2015)
Recent Advances in the Mitigation of Tin Whiskers from Electroplated Tin
New Mexico Tech
Tin whiskers pose an electrical reliability risk in the form of potential short circuits.
problem was solved in the past by adding a few percent of Pb during Sn electroplating, but with
the ban on Pb it has resurfaced. While various mitigation strategies have been formulated based
on known whisker growth mechanisms, the electronic industry is still awaiting a satisfactory
solution to the whisker growth problem in Pb-free electronics. Recent advances in the
understanding and mitigation of whiskers are reviewed. The effects of various alloying
elements/dopants are discussed in terms of the mechanisms that impact whisker growth kinetics
and mitigation. In more recent work, we have demonstrated that indium addition to Sn eliminates
whiskers with even better mitigation performance than Pb. The mechanisms are discussed, in
particular the important role of indium on the surface oxide and subsurface enrichment.
Ref: B.S. Majumdar, I. Dutta, S. Bhassyvasantha, S. Das Mahapatra, J. of Metals. 72(2), 906-917 (2020)
On the use of Barrier Films to Prevent Corrosion
New Mexico Tech
Corrosion occurs when a metal reacts with the environment and degrades, either by cracking, pitting or thinning. A common method to prevent corrosion is to use barrier films that separate the metal from its environment. These barrier films can take many different forms, including painting a metal, or passivating the metal with an oxide film. This seminar will introduce the common barrier films, and then describe some of the author’s research on creating barrier films on different metals. The research examples will include the oxides that can be grown on the surface of titanium, on aluminum, and on Ni-Ti shape memory alloys, and methods to anodize steel, and also introduce self-assembled thiol monolayers on silver or copper alloys.