Progress towards Understanding the Synthesis and Behavior of Metals Far from Equilibrium: A SMD Symposium Honoring Enrique Lavernia on the Occasion of His 60th Birthday: Materials Design and Advanced Characterization
Sponsored by: TMS Structural Materials Division, TMS: Mechanical Behavior of Materials Committee, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Composite Materials Committee
Program Organizers: Haiming Wen, Missouri University of Science and Technology; Suveen Mathaudhu, Colorado School of Mines; Yuntian Zhu, City University of Hong Kong; Manoj Gupta, National University of Singapore; Kaka Ma, Colorado State University; Troy Topping, California State University Sacramento; Yizhang Zhou, University of California, Irvine; Joshua Yee, Sandia National Laboratories; Dalong Zhang, Pacific Northwest National Laboratory; Yaojun Lin, Wuhan University of Technology; Fei Chen, Wuhan University of Technology
Tuesday 2:00 PM
February 25, 2020
Room: 31B
Location: San Diego Convention Ctr
Session Chair: Fei Chen, Wuhan University of Technology; Josh Yee, Sandia National Laboratory
2:00 PM Invited
Phase Separation in a Ni-Al-Cr-Re Alloy: Kinetics and Thermodynamics Coupled with Atom-probe Tomography: David Seidman1; 1Northwestern University
Phase-separation of a Ni-10Al-8.5Cr-2Re at.% alloy aged at 973 K is studied from 0 to 1024 h, by atom-probe tomography, where the gamma (f.c.c.) and gamma-prime (L12) composition trajectories are displayed in a tetrahedron, whose apexes correspond to Ni, Al, Cr and Re. The gamma-prime precipitates are nucleated deep inside the gamma-prime phase-field and they have a composition trajectory that evolves toward a curved gamma-prime solvus-surface. The composition trajectory of the gamma (f.c.c.)-phase commences in the (gamma plus gamma-prime phase field) at the mean composition of this quaternary alloy, which moves along a trajectory toward the curved conjugate gamma-solvus surface. The composition trajectory of the gamma-prime precipitates encompasses nucleation, growth and coarsening and it is curvilinear. The composition trajectory of the gamma phase reflects changes in the matrix’s composition. The tie-line between gamma- and gamma-prime-phases is determined by the end-point compositions of the two-phases on the two conjugate solvus surfaces.
2:30 PM Invited
New Electron Microscopy Techniques for Determination of Local Structural Features during Plastic Deformation: Andrew Minor1; 1University of California, Berkeley
This talk will highlight recent advances in Transmission Electron Microscopy (TEM) techniques that provide insight into small-scale plasticity and the evolution of defect structures in materials. Through the development of fast direct electron detectors, it is now possible to acquire large multidimensional data sets of nanodiffraction patterns (4D-STEM) that can map local structural order and strain with nanometer precision, even during in situ nanomechanical testing. The method is widely applicable and examples will be given from systems such as organic semiconductor molecular thin films, structural alloys with local order such as Ti-Al and CrCoNi medium entropy alloys, and even to amorphous samples such as bulk metallic glass. This talk will describe our recent results utilizing fast direct electron detectors, energy filtered imaging and in situ TEM nanomechanical testing that provide insight into multiscale materials phenomena using these techniques.
3:00 PM Invited
Structural and Chemical Disorder Towards Advanced Materials: Horst Hahn1; 1Karlsruhe Institute of Technology
Advanced materials are typically characterized by complex nano- and microstructures with various phase compositions, grain sizes, chemical inhomogeneity or homogeneity, crystalline and amorphous structures, all leading to metastability. Over the past 30 years, many new materials have been developed making use of these possibilities and leading to many interesting properties. Prominent examples of such materials are metallic glasses, nanocrystalline materials and high entropy alloys. In recent years, new ideas and novel synthesis routes have shown the way to advanced materials with yet unknown structures and properties. The talk will present examples of synthesis, characterization and properties of advanced materials with amorphous and crystalline structures: nanoglasses, cluster-assembled amorphous and crystalline materials and high entropy oxides.
3:30 PM Break
3:50 PM Invited
Materials Genomics: Designing Systems Far from Equilibrium: Gregory Olson1; 1Northwestern University
Sixty years of academic collaboration and thirty years of commercialization by a network of small businesses have delivered a mature technology of computational materials design and accelerated qualification grounded in a system of fundamental databases now known as the Materials Genome. Application of thermodynamic and kinetic databases to systems far from equilibrium span martensitic transformations, precipitation at high supersaturation, and rapid solidification phenomena. Recent designs address alloy optimization for the new technology of additive manufacturing, exploiting the combination of boiling melts and rapid solidification. A printable Sc-free L12-strengthened Al alloy provides exceptional strength at 250-300C via a novel multiphase microstructure achievable only by the unique processing pathway of additive manufacturing.
4:20 PM Invited
A Precise DSC-based Methodology to Pinpoint in situ Crystallinity Percent in Amorphous Systems: Olivia Graeve1; Arash Yazdani1; Günther W.H. Höhne2; Darren Dewitt1; Javier E. Garay1; 1University of California, San Diego; 2Ulm University
An understanding of the crystallization of amorphous materials is of critical importance, since devitrification products and kinetics strongly affect the properties of the resulting materials. However, there are some amorphous systems whose crystallization behavior cannot be quantified by conventional methods such as X-ray diffraction and scanning/transmission electron microscopy. We have developed a differential scanning calorimetry (DSC) methodology to calculate the change in crystallinity and crystallinity percentage as a function of temperature in amorphous systems. By comparing the enthalpies of amorphous, crystalline and partially devitrified samples, we implemented a mathematical description. We have succeeded in measuring crystallinity percentages as small as 5% with an uncertainty of 1.6% for amorphous steels. This novel method can also deliver crystallinity information without the use of expensive and high maintenance in situ accessories. A comparative analysis between percent crystallinity and the microstructure from samples prepared by spark plasma sintering will also be described.
4:50 PM Invited
Hot Corrosion Degradation of Gas Turbine Materials Subject to Mixed-mode Thermal Exposures and Emerging Complex Corrosion Environments: Kliah Soto Leytan1; Kunthea Deng1; Maryam Zahiri Azar1; Daniel Mumm1; 1University of California, Irvine
Turbine engines are pervasive in marine environments, used as aircraft and ship propulsion systems and power generation units. The performance of hot-section materials is dependent upon the exposure temperatures and the corrosive conditions associated with the salt-laden environment. Emerging turbine service needs result in increasingly aggressive/variable duty cycles and more complex deposit chemistries. While basic mechanisms governing sulfate-induced accelerated degradation are fairly well established, an understanding of the effects of microstructural heterogeneities, ingestion of atmospheric particulate matter, and widely varying thermal exposures is lacking. Recent findings show that alkaline earth oxides and silicates ingested as atmospheric contaminants play an exacerbating role in the attack rate for alloys and coatings. Herein, we explore the synergistic effects of mixed-mode thermal cycles and complex deposit chemistries containing sulfates, silicates and/or oxides. Correlations are drawn between the observed degradation mechanisms and the simulated service exposures utilizing controlled-environment testing coupled with high-resolution materials characterization approaches.
5:20 PM
Time-Resolved Characterization of Far-from-equilibrium Microstructure Evolution During Rapid Solidification: Joseph McKeown1; John Roehling1; Tian Li1; Alexander Baker1; Scott McCall1; Kai Zweiacker2; Amy Clarke3; Jörg Wiezorek4; 1Lawrence Livermore National Laboratory; 2Empa, Swiss Federal Laboratories for Materials Science and Technology; 3Colorado School of Mines; 4University of Pittsburgh
The dynamic transmission electron microscope (DTEM) at Lawrence Livermore National Laboratory (LLNL) was developed to enable in situ multi-frame image acquisitions (i.e., movies) of rapidly evolving, far-from-equilibrium materials processes with nanometer spatial and nanosecond temporal resolutions. Here, work will be presented from laser-induced rapid solidification (RS) experiments in Al-based alloys. RS occurs in numerous manufacturing processes involving metallic alloys, such as laser welding and additive manufacturing (AM), and results in processing conditions (large thermal gradients, high cooling rates and solidification front velocities) that produce highly non-equilibrium microstructures. DTEM allows direct observation of RS microstructure evolution and measurements of kinetics. The effects of solute species (Cu, Ag, Ce), temperature gradient, and solidification rate on phase selection and morphology will be presented, with complementary in situ heat treatments to assess thermal stability of RS microstructures and ex situ postmortem microstructure evaluation.
5:40 PM
Computed Tomography: A New Frontier for Material Characterization: Chen Yee1; 1Vj Technologies
Material characterization techniques are often destructive and/or limited in scope with respect to relevant sampling volumes. Destructive techniques can be self defeating for examination of in-service components, while techniques with limited sampling volumes may not reveal the complete story of fundamental material behavior. Recent advances in NonDestructive Evaluation (NDE) techniques may be able to help bridge these gaps. In particular, computed tomography (CT) and its derivatives could be useful as powerful new tools that do not destroy materials, while also easily collecting large, relevant volumes for more complete analysis. In this presentation, we will discuss how CT techniques can supplement existing material characterization techniques for process optimization, quality assurance, and failure analysis.
6:00 PM Cancelled
3D Morphological Evolution of Bimodal Porous Copper Characterized by X-ray Nano-tomography: Fei Chen1; Lijie Zou1; Hao Wang1; Mingyuan Ge2; Chonghang Zhao3; Wah-Keat Lee2; Xianghui Xiao2; Karen Wiegart3; 1Wuhan University Of Technology; 2National Synchrotron Light Source-II, Brookhaven National Laboratory; 3School of Materials Science and Chemical Engineering, The State University of New York at Stony Brook
The bimodal porous Cu consists of two different pore sizes – micron-sized pores to improve mass transfer efficiency and nano-sized pores to improve mechanical strength, thus giving the porous metal unique functionality and further improving porosity. In this study, Cu-Fe-Al ternary precursor alloy was dealloyed to prepare bimodal porous Cu. By this method, we achieved the goal of preparing porous Cu with high porosity and multiscale porous structure. The composition of precursor alloy was adjusted to control the microstructure of bimodal porous Cu. Moreover, the 3D morphological evolution and oxidation state of Cu-Fe-Al alloy during dealloying process were also studied in this work through conducting interrupted in-situ X-ray nano-tomography technique (Full Field X-ray Imaging Beamline, National Synchrotron Light Source-II, Brookhaven National Laboratory, USA). The porous structure parameters were quantified using the segmented 3D images to further clarify the formation mechanism of bimodal porous structure.