Materials Design Approaches and Experiences V: High Entropy Alloys and High Temperature Alloys
Sponsored by: TMS Structural Materials Division, TMS: High Temperature Alloys Committee, TMS: Integrated Computational Materials Engineering Committee
Program Organizers: Akane Suzuki, GE Aerospace Research; Ji-Cheng Zhao, University of Maryland; Michael Fahrmann, Haynes International; Qiang Feng, University of Science and Technology Beijing; Michael Titus, Purdue University
Wednesday 8:30 AM
February 26, 2020
Room: 33A
Location: San Diego Convention Ctr
Session Chair: Martin Heilmaier, Karlsruhe Institute of Technology; Akane Suzuki, GE Research
8:30 AM Invited
Design Principles for Complex, Concentrated Alloys (CCAs): Daniel Miracle1; 1Air Force Research Laboratory
The number of new alloy bases has exploded in recent years with the concepts of high entropy alloys (HEAs) and complex, concentrated alloys (CCAs), driving the need for accelerated methods to explore and design new alloys. At the same time, new tools for designing and characterizing alloys have continued to grow. This talk will evaluate this convergence of needs and opportunities by reviewing strategies to rationally explore the vast number of new alloy bases provided by CCAs and by evaluating the growing set of computational and experimental tools and techniques to design new alloys. Areas of synergy as well as remaining technology gaps will be identified and discussed.
9:00 AM Invited
Oxidation Resistant Refractory Metal High Entropy Alloys for Ultrahigh Temperature Structural Applications: Bronislava Gorr1; Steven Schellert1; Franz Mueller1; Stephan Laube2; Hans Chen2; Alexander Kauffmann2; Hans-Juergen Christ1; Martin Heilmaier2; 1University of Siegen; 2KIT Karlsruhe
We report on our development status of refractory metal based high entropy alloys for ultrahigh temperature structural engineering materials. Different alloys within the system Nb-Ta-Mo-Cr-Ti-Al were synthesized by arc melting. Applying suitable homogenization treatment leads to the presence of a single phase with B2 order at low temperatures T which is in some alloys responsible for a brittle-to-ductile transition occurring between 600 and 1000 °C. Solid solution hardening below BDTT is predicted using the atomic size difference as main relevant parameter. Elevated temperature behavior was investigated utilizing compression creep (T = 900…1100 °C) and continuous and cyclic oxidation tests in laboratory air in an even wider range of T between 500 and 1500 °C. Promising properties were noted, in particular TaMoCrTiAl forms a protective CrTaO4 scale which exhibits very low growth rates and is well adherent. Thus, it is responsible for low weight gains and the absence of catastrophic oxidation.
9:30 AM Invited
Materials Parameters in Designing FCC High-entropy Alloys: Haruyuki Inui1; Koudai Niitsu1; Kyosuke Kishida1; Easo George2; 1Kyoto University; 2University of Tennessee
High-entropy alloys (HEAs) comprise a novel class of scientifically and technologically interesting materials. Among these, equatomic CrMnFeCoNi and its derivative quaternary and ternary alloys with the FCC structure are noteworthy because their strengths are by far higher than those of conventional FCC alloys and their tensile ductility increases with decreasing temperature while maintaining outstanding fracture toughness. It is indispensable to find out proper materials parameters that predict the strength and ductility in designing HEAs with high strength/ductility. Since the high ductility at low temperatures is reported to arise from the occurrence of deformation twinning, stacking fault energy must in principle be responsible, while the strength seems to be correlated with the mean-square atomic displacement (MSAD) from the regular FCC lattice points. MSAD and stacking fault energy are discussed in terms of how and to what extent whey can be used to predict the strength and ductility of HEAs.
10:00 AM
Design of Ni-Co-Ru Multi-principal Elements Alloys: Marie Charpagne1; K. Vamsi1; Carolina Frey1; Yolita Eggeler1; Sean Murray1; Tresa Pollock1; 1University of California, Santa Barbara
Toward the goal of designing new strong yet ductile multi-principal element face-centered cubic alloys, materials with potentially low stacking fault energies have been targeted. Exploration of phase equilibria via thermodynamic databases highlighted the Ni-Co-Ru ternary as a potentially promising system. Following first-principles calculations, several Ni,Co,Ru alloys of stable FCC structure have been cast and thermo-mechanically processed. Among them, the Ni2Co2Ru compound exhibits a higher yield strength compared to the well-studied NiCoCr ‘medium-entropy’ alloy. It is also very prone to deformation twinning, at room temperature and up to 400-600°C, where slip becomes the main deformation mechanism. The deformation mechanisms as a function of strain and temperature will be discussed in detail, supported by calculations of planar fault energies.
10:20 AM Break
10:40 AM Invited
Development of HAYNES® 233® Alloy: Lee Pike1; S. Srivastava1; 1Haynes International
HAYNES 233 alloy was developed to fill a need in the marketplace for a readily fabricable superalloy with both excellent oxidation resistance and high creep strength at temperatures up to 2100°F (1149°C). While there are a number of fabricable alloys with high creep strength at these temperatures (230® alloy, 617 alloy, etc.), they generally rely on chromia-formation to provide oxidation resistance. Conversely, existing fabricable alloys (such as 214® alloy) which have sufficient Al to produce a protective alumina scale generally suffer from poor creep strength at temperatures above the gamma-prime solvus. The new 233 alloy combines both properties while still having the capability to be welded, hot worked, cold worked, etc. The development of 233 alloy will be presented along with some details of the alloy research which led to its invention.
11:10 AM
Accelerated Design of High-temperature Alloys with Data Analytics and Supercomputing: Jian Peng1; Andrew Williams2; Sangkeun Lee1; Yukinori Yamamoto1; J. Haynes1; Dongwon Shin1; 1Oak Ridge National Laboratory; 2Cornell University
We present a modern data analytics framework that has the potential to accelerate the design of high-temperature alloys significantly. Our starting point is a series of machine learning models that can predict creep properties of alumina-forming austenitic (AFA) alloys, trained with a decade of ORNL’s consistent experimental data augmented with key thermodynamic features (e.g., volume fraction and degree of supersaturation) calculated from a state-of-the-art computational thermodynamic database. We use a design of experiments (DOE) approach to populate tens of thousands of hypothetical AFA alloys as inputs for machine learning models. The thermodynamic features of each virtual alloy have been computed with ORNL’s world-class supercomputer to generate a substantial volume of synthetic data in a high-throughput manner. We have identified a number of promising AFA alloys with improved creep, for future experimental validation. This research was sponsored by the Department of Energy, Vehicle Technologies Office, Propulsion Materials Program.
11:30 AM
Materials Discovery and Design using Heritage Data: Amit Verma1; Jeffrey Hawk2; Vyacheslav Romanov3; Jennifer Carter1; 1Case Western Reserve University; 2National Energy Technology Laboratory, Albany; 3National Energy Technology Laboratory, Pittsburgh
Heritage data for different classes of high-temperature alloys was studied using machine learning to accelerate the materials discovery for the next generation of materials with better creep strength and toughness. Visualization techniques such as t-distributed stochastic neighbor embedding were utilized to explore the information gaps that exist within the data and regression methods such as linear and lasso regression were utilized to identify the alloying elements that contribute to creep strength, tensile strength, and ductility. The talk will focus on limitations of data for data-driven studies, highlight the importance of data collection for future studies, and will go through contemporary power-law creep methodologies that were used to reduce the timeline for materials selection. Overall, this work contributes to the field of materials design by (1) employing machine learning to highlight the missing opportunities, and (2) emphasizing that well constructed design space can accelerate the discovery of new materials.
11:50 AM
Application of Computational Tools in Designing Ni-base Single-crystal Superalloys: Akane Suzuki1; Chen Shen1; Natarajan Chennimalai Kumar1; 1GE Research
Alloy design is critical to achieving the target performance of industrial components and products. In designing new alloys, there are multiple property requirements, including mechanical, environmental, and physical properties, as well as manufacturability and processability. Computational models and tools to predict properties from alloy compositions and to optimize compositions for multiple objectives are essential in enabling efficient, robust alloy design. Data-driven property models by machine learning (ML) are particularly useful in predicting physical properties with relatively simple dependence on composition, and in predicting complex properties that are too difficult for a physics-based model to achieve with desirable accuracy. In this presentation, we describe examples of ML applications to model coefficient of thermal expansion, creep and fatigue resistance in designing Ni-based superalloys, and optimization methodologies. We also discuss physics-based microstructure models that have been developed for optimizing heat-treatment conditions to achieve desired microstructures.