High Entropy Materials: Concentrated Solid Solution, Intermetallics, Ceramics, Functional Materials and Beyond: Materials Discovery and Design I
Sponsored by: ACerS Basic Science Division, TMS Alloy Phases Committee
Program Organizers: Xingbo Liu, West Virginia University; Michael Gao, National Energy Technology Laboratory; Peter Liaw, University of Tennessee; Jian Luo, University of California, San Diego; Yiquan Wu, Alfred University; Yu Zhong, Worcester Polytechnic Institute
Monday 8:00 AM
November 2, 2020
Room: Virtual Meeting Room 33
Location: MS&T Virtual
Session Chair: Xingbo Liu, West Virginia University; Mike Widom, Carnegie Mellon University
8:00 AM
Introductory Comments: High Entropy Materials: Xingbo Liu1; 1West Virginia University
Introductory Comments
8:05 AM Keynote
The Department of Energy’s High Performance Materials Program and Its High Entropy Alloy R&D: Briggs White1; 1U.S. Department of Energy - NETL
The US Department of Energy, Office of Fossil Energy sponsors a High Performance Materials program, which is managed by the National Energy Technology Laboratory (NETL). This program enhances the nation’s industrial high-temperature materials supply chain by accelerating the development of improved steels, superalloys, and new advanced manufacturing methods, completing full-scale manufacturing trials of power plant components, and creating solutions to address challenges for both the existing fleet and future power systems. The program spans several areas of research such as Computational Materials Design, Advanced Structural Materials, Functional Materials for Process Performance and Advanced Manufacturing, and seeks to solve various costs and challenges faced by multiple industries. In the context of this symposium, past and current work related to high entropy alloys sponsored by the program will be reviewed along with a more general update on the various other materials being developed for extreme environments.
8:45 AM Invited
Beyond Mechanical Metastability in FeMnCoCr?: Haoxue Yan1; Maria Ronchi1; Shaolou Wei1; C. Tasan1; 1Massachusetts Institute of Technology
Hydrogen embrittlement is one of the most significant challenges limiting the use of high-strength alloys, especially those which benefit from transformation-induced plasticity (TRIP) effect. In this study, we investigate the effect of hydrogen on austenite stability in Fe-Mn based metastable high entropy alloys, by utilizing a home-developed scanning electron microscopy – thermal desorption spectroscopy (SEM-TDS) technique. We demonstrate that the introduction of hydrogen in these alloys can influence not only austenite stability, but also extension twin formation within the strain-induced HCP-martensite. By analyzing these alloys with integrated SEM/EBSD and crystallographic analyses, we reveal the underlying twinning micro-mechanisms. In the talk we will also discuss the exploration of such effects to create feasible pathways to extend the property improvement limits of classical TRIP assisted alloys.
9:05 AM Invited
High-Entropy Alloy Approach to Thermoelectric Materials: Joseph Poon1; 1University of Virginia
High-Entropy Alloys (HEA) are emerging compositionally complex materials that show promise in structural and functional properties [1]. Before the invention of HEAs, multi-element-alloy approach had been employed to improve the thermoelectric properties. One example was TAGS (Te-Sb-Ge-Ag) that showed a figure of merit near 1. Other examples have included half-Heusler and chalcogenide compounds [2]. Some of these materials resembled HEAs. Since the discovery of high-entropy alloys in 2004, a new concept has emerged for the systematic exploration of crystal structure, lattice disorder, electronic structure, and microstructure in finding new thermoelectric alloys. This talk will highlight the recent development by providing specific examples and also looking into the future [3]. [1] M. C. Gao and D. B. Miracle, et al, J. Mater. Res. 33, 3138 (2018). [2] R. Liu, et al., Adv. Mater. 29, 1702712 (2017).[3] S. J. Poon and J. He, in Encyclopedia of Materials: Metals and Alloys.
9:25 AM Invited
Computational Techniques to Study High-entropy Materials: Stefano Curtarolo1; 1Duke University
In this presentation we will review recent advances in computational techniques to study and discover high-entropy materials. Research sponsored by DOD and NSF.
9:45 AM Invited
The Role of Large Static Displacements in Stabilizing BCC High Entropy Alloys: German Samolyuk1; Yuri Osetsky1; Malcolm Stocks1; James Morris2; 1Oak Ridge National Laboratory; 2Ames Laboratory
We present a density functional theoretical exploration of phase stability and competing crystal structures in medium and high entropy alloys formed of group IV and V elements. We find that configurational disorder may determine the crystal structure, even at low temperatures where entropic considerations are minimal. The static displacements are much larger for the body centered cubic (BCC) phase than is seen in face centered cubic high entropy alloys, and these displacements help stabilize the BCC phase. In some cases average displacements approach 10% of the near-neighbor distance, close to the Lindemann criterion for melting. The large displacements mimic temperature-driven fluctuations that stabilize the BCC phase in Ti, Zr and Hf.This work is supposed by the Department of Energy’s Office of Science, through the Energy Dissipation to Defect Evolution EFRC (GDS, YO and GMS), and through the Materials Science and Engineering Division (JRM).
10:05 AM Invited
Computationally Guided High Entropy Alloy Discovery: John Sharon1; Ryan Deacon1; Soumalya Sarkar1; Kenneth Smith1; 1UTRC
High entropy alloys (HEA), composed of multiple principal elements, have been demonstrated to have enhanced properties compared to conventional systems. While this class of materials holds exciting potential for numerous industrial and aerospace applications the option space of possible HEAs is still largely unexplored as billions of compositions exist for alloys that contain 4 or more elements. This talk will highlight a machine learning-based framework which is able to converge on a set of HEA candidates given a large set of design objectives and constraints. The proposed approach demonstrates scalability to comprehensive HEA space exploration even while receiving data from variably expensive physics-based thermo-mechanical models. Data from test coupons as well as the open literature can also be incorporated into this framework to aid in the reliability of the overall framework. Examples of framework prediction with corresponding experimental validation will also be discussed.
10:25 AM Invited
Using Machine Learning, CALPHAD, and DFT to Accelerate Materials Development: Kenneth Vecchio1; Kevin Kaufmann1; 1University of California, San Diego
For the past decade, considerable research effort has been devoted toward computationally identifying and experimentally verifying single phase, high-entropy systems. However, predicting the resultant crystal structure(s) “in silico” remains a major challenge. Previous studies have primarily used density functional theory to obtain correlated parameters and fit them to existing data. This strategy is impractical given the extensive regions of unexplored composition space, the relatively small amount of data available, and considerable computational cost. Machine learning has inherent advantages over traditional modeling owing to its flexibility as new data becomes available and its rapid ability to construct relationships between input data and target outputs. Using a combination of CALPHAD and chemical attributes in a machine learning framework, we demonstrate the ability to augment DFT methodologies and predict the likelihood of successful synthesis for a given composition, thus allowing exploration of material space in an unconstrained manner; several specific examples are demonstrated.