High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond III: Materials Discovery and Design II & Theory and Modeling II
Sponsored by: TMS: Nanomaterials Committee
Program Organizers: Yu Zhong, Worcester Polytechnic Institute; Michael Gao, National Energy Technology Laboratory; Xingbo Liu, West Virginia University; Peter Liaw, University of Tennessee; Jian Luo, University of California, San Diego; Yiquan Wu, Alfred University; Mitra Taheri, Johns Hopkins University; Amy Clarke, Los Alamos National Laboratory

Wednesday 2:00 PM
October 12, 2022
Room: 324
Location: David L. Lawrence Convention Center

Session Chair: Prashant Singh, Ames Laboratory of US DOE; Mitra Taheri, Johns Hopkins University


2:00 PM  Invited
Theory-guided Design of Refractory Alloys for Ultra-high-temperature Applications: Prashant Singh1; Gaoyuan Ouyang1; Matthew J Kramer1; Jun Cui1; Duane D Johnson1; 1Ames Laboratory
    Refractory alloys are promising candidates to replace Ni-based superalloys for high-temperature applications, such as gas-turbine blades, due to their exceptional mechanical properties at high temperatures. We analyzed key alloy features in solid-solution phases, such as phase stability, oxidation, chemical ordering, and defects energies as well as mechanical strength and intrinsic ductility using machine-learning. Density-functional theory (DFT) methods were employed to analyze the role of lattice distortion, electronegativity, and defect concentration on mechanical behavior of ML predicted compositions. We show that ML combined with DFT is able to capture the key structure-property trends. We also discuss a novel theoretical approach to characterize ductility in bcc refractory alloys. Bulk combinatorial arc-melt synthesis and characterizations were performed for validation and down-selection of compositions with superior mechanical properties. This work seeks to bridge existing gaps in refractory multiple-principal element alloy development.

2:20 PM  
Towards to an ICME Approach for the Discovery of the Lightweight High Entropy Alloys: Shengyen Li1; Jianliang Lin1; John Macha1; Mirella Vargas1; Michael Miller1; 1Southwest Research Institute
    This presentation will discuss the feasibility of integrating high throughput experiments (HTE) with computational approaches to discover composition spaces for lightweight high entropy alloys (LHEAs). The objectives are to reduce density by 25% while the mechanical properties comparable to Ni-based superalloys for high temperature applications. To explore the potential space cost-effectively, the first iteration of the material discovery focuses on data gathering, knowledge managing, and design of experiments. A data-handling tool is developed to parse, analyze, and save data from literatures and experiments. The statistical functions and machine learning algorithms follow the data gathering to clean-up and map-out high dimensional information for the development of the alloy-structure-properties relationships in an effective fashion. This informatics system also integrates with a preliminary modeling hierarchy and Monte Carlo tool to select the potential composition space for the subsequent high throughput experimentations. The outcomes guide the iterative experiments to achieve the goal of discovery.

2:40 PM  
High-throughput Approach for Stacking Fault Energies in HEAs: Jize Zhang1; Yu Zhong1; 1Worcester Polytechnic Institute
    Transformation/twinning-induced plasticity (TRIP/TWIP) significantly impact material properties like strength and ductility in alloys. Stacking fault energies (SFE) play an essential role in determining TRIP/TWIP mechanisms, and thus a close examination of SFE is crucial for predicting and controlling the mechanical properties of TRIP/TWIP alloys. In the current work, we investigate TRIP/TWIP in high entropy alloys (HEA) by modeling stacking fault energies. The intricate nature of phases present in HEAs gives both opportunities and challenges in material design. Therefore, we will use a high throughput approach with computational methods to effectively and efficiently calculate the stacking fault energies and then determine the plastic deformation mechanisms through numerous compositions. With the high throughput results, we can comprehensively understand TRIP/TWIP in high entropy alloys and improve material designs.

3:00 PM  
Atomic Mobility Assessment of the fcc Ternary Co–Cr–Mn Alloy: Sri Pragna Pendem1; Nobufumi Ueshima1; Katsunari Oikawa1; 1Tohoku University
    The atomic mobility parameters of the fcc ternary Co–Cr–Mn system, which is a sub-alloy of the Cantor alloy, were determined in this study. Composition profiles measured using EPMA (electron probe microanalyzer) after heat-treating the diffusion couples at 900, 1050, and 1150 °C were used to obtain flux by using Whittle-Green method. Values of flux obtained experimentally were used to determine the atomic mobility parameters using an in-house python program and Nelder-Mead optimization technique. Atomic mobility parameters obtained in this study were validated by comparing the experimental and simulated concentration profiles at three temperatures. The kinetic assessments in this study will facilitate the development of kinetic databases for HEAs.