Advances in Multi-Principal Element Alloys II: Alloy Development and Application II
Sponsored by: TMS Structural Materials Division, TMS Functional Materials Division, TMS: Mechanical Behavior of Materials Committee, TMS: Alloy Phases Committee
Program Organizers: Peter Liaw, University of Tennessee; Michael Gao, National Energy Technology Laboratory; E-Wen Huang, National Yang Ming Chiao Tung University; Jennifer Carter, Case Western Reserve University; Srivatsan Tirumalai; Xie Xie, FCA US LLC; James Brechtl, Oak Ridge National Laboratory; Gongyao Wang, Globus Medical
Monday 2:00 PM
March 20, 2023
Room: Aqua D
Location: Hilton
Session Chair: Joseph Poon, University of Virginia; Jennifer Carter, Case Western Reserve University
2:00 PM Invited
The Challenges of High-Entropy Intermetallic Alloys: Joseph Poon1; Jie Qi1; 1University of Virginia
High-entropy alloy (HEA) solid solutions of simple structures (fcc, bcc, and hcp) can now be classified and predicted with considerable accuracy using various data-driven methods. However, predicting high-entropy intermetallic alloys (HEIA) and their composite alloys that are usually associated with functional properties, e.g., half-metallic, multiferroic, magnetocaloric, thermoelectric, and topologically-nontrivial, etc., are still under-developed. Modeling HEIA is often constrained by the availability of datasets and the effectiveness of descriptors. We have developed physics-based and compound-specific models to explore the complex compositional landscape of HEIA through feature engineering and experimentation. The high prediction capability of the models enables the design of ordered BCC (B2) and Heusler (L21) HEI for high-performance properties.
2:20 PM Invited
Charged Particles: Unique Tools to Study Irradiation Resistance of High-entropy Alloys: Yanwen Zhang1; Lumin Wang2; William Weber3; 1Oak Ridge National Laboratory; 2University of Michigan; 3The University of Tennessee
Some multicomponent concentrated solid solution alloys, including high-entropy alloys (HEAs), exhibit improved radiation resistance and enhanced structural stability in harsh environments. Energetic ions and electrons are commonly used to create displacement damage for studying the performance of irradiation resistance. Moreover, charged particles, including ions, electrons, and positrons, are unique tools to characterize radiation effects. Applications of charged particles to study irradiation resistance of HEAs are discussed to demonstrate their unique ability to understand radiation damage. In developing structural alloys desirable for applications in advanced reactors, neutron exposure is a critical test but the limitation in achievable high damage levels is a bottleneck. Ion irradiation is often used as a surrogate for neutron irradiation, but cautions need to be taken when relay ion irradiation results for reactor applications. Links to bridge the current advances on fundamental understandings to reactor applications are discussed.
2:40 PM Invited
Developing TRansformation-Induced-Plasticity (TRIP) TiZrHf(VNbTa)x High-entropy Alloys via Bo-Md Diagram: Gian Song1; Yunjong Jung1; Kangjin Lee1; Jiwoon Lee1; Junhee Han2; Ke An3; Chanho Lee4; Peter Liaw5; 1Kongju National University; 2Korea Institute for Rare Metals, Korea Institute of Industrial Technology (KITECH); 3Oak Ridge National Laboratory; 4Los Alamos National Laboratory; 5The University of Tennessee
High-entropy alloys (HEAs) have been studied due to their unique microstructures and mechanical properties. Refractory high-entropy alloys (RHEA) exhibit outstanding mechanical properties, high temperature strength, creep resistance, and thermal stability. Nevertheless, most of RHEAs show high strength but low ductility at room temperature. Because of the limited ductility, RHEAs are less compatible with industrial applications than FCC-HEAs. For this reason, several alloy design strategies to tailor phase stability resulting in occurrence of mechanical phase transformation had been attempted to improve ductility with maintaining their high strength.In this study, we developed refractory HEAs with the transformation-induced-plasticity (TRIP). To design TRIP-HEAs, we adopted Bo-Md diagram, which is known as a phase-stability diagram. This diagram allows for prediction of structural stability. To control Bo-Md values, we systematically designed Ti-Zr-Hf-V-Nb-Ta alloys, and investigated microstructure and deformation behavior, using scanning-electron microscope, energy-dispersive spectroscope, X-ray diffraction, electron-backscatter diffraction, in-situ neutron diffraction.
3:00 PM Invited
Ion-beam Modification of High-entropy Oxides: William Weber1; Candice Kinsler-Fedon1; Lauren Nuckols1; Anamul Mir2; Brianna Musico1; Ashish Gupta3; Ritesh Sachan3; Christopher Nelson4; David Mandrus1; Yanwen Zhang4; Veerle Keppens1; 1University of Tennessee; 2University of Huddersfield; 3Oklahoma State University; 4Oak Ridge National Laboratory
High-entropy oxides have recently gained recognition for their low thermal conductivity and tunable mechanical capabilities, but little is known about their response to ion irradiation. In this work, the heavy-ion irradiation response of high-entropy oxides (HEO) with the pyrochlore and perovskite structures have been investigated. The damage accumulation behavior at 300 K due to 4 MeV Au ion irradiation of a <100>-oriented HEO titanate pyrochlore single crystal has been investigated by Rutherford backscattering spectrometry in channeling geometry. Transmission electron microscopy with in situ irradiation using 600 keV Xe ions has been employed to determine the temperature dependence of amorphization in the same HEO pyrochlore composition. Ion tracks formed in a HEO perovskite structure irradiated with 774 MeV Xe ions have been characterized by transmission electron microscopy. The results obtained on these HEOs are compared to those of single-component counterparts.
3:20 PM Invited
High Entropy Alloy Metamaterials: Dustin Gilbert1; Corisa Kons1; Cameron Jorgensen1; 1University of Tennessee
High entropy alloys (HEAs) have been broadly presented as an ideal structural material, with recent works also showing promise for their functional properties, including magnetic, thermoelectric, catalytic, and biomedical. Recently, we have developed nanostructured HEAs in the form of electrodeposited nanowires of (Cr,Fe,Ni,Co,Cu). These nanowires were then structured to prepare an ultra-low density (<0.1% bulk weight) metamaterial – termed a nanowire scaffold. The nanowires were then welded, resulting in a ridged structure. These structures present new opportunities for specialized applications in weight sensitive technologies and high surface area applications such as catalysts. This work presents the fabrication of the nanowire scaffolds, their structural properties and functional properties (magnetic, electronic).
3:40 PM Break
4:00 PM Invited
Combined Machine Learning – Graph Theory Based Framework for the Design of New High Entropy Alloy Chemistries: Scott Broderick1; Krishna Rajan1; 1University at Buffalo
This work uses a graph representation approach to capture the thermodynamic and structural complexity of high entropy alloys (HEAs) to identify new chemistries with an enhanced combination of strength, ductility and environmental effects. The advantage of the graph-based approach is that it incorporates numerous criteria for design (including mechanical and environmental properties, as well as microstructure) to identify HEA compositions when there are trade-offs between the various criteria. By mapping the high dimensional nature of the systematics of elemental data embedded in the periodic table into the form of a network graph, one can uncover the influence of specific combinations elements on engineering properties of HEAs. In this way, mechanical and environmental properties are rationally designed through proposed chemical design rules across the entire HEA search space, resulting in a machine learning based representation of a periodic table based on HEA properties.
4:20 PM Invited
Compositionally Complex Ceramics (CCCs): Recent Discoveries of Long- and Short-Range Ordering and Order-Disorder Transitions: Jian Luo1; 1University of California, San Diego
Various single-phase equimolar five-component high-entropy ceramics (HECs), e.g., MB2 [Scientific Reports 2016], MB [Scripta 2020], M3B4 [JAC 2021], MB4 [JECS 2020] and MB6 [JECS 2021] borides, MSi2 [JMat 2019] and M3Si5 [Scripta 2022] silicides, aluminides [Science Bulletin 2019], perovskite [Scripta 2018], fluorite [JECS 2018] and pyrochlore [Scripta 2020] oxides have been fabricated. We further proposed to extend HECs to "compositionally complex ceramics (CCCs)" [JECS 2020 and JMS 2020] in include non-equimolar compositions and short- and long-range ordering (that reduce configurational entropies but offer additional dimensions to tailor and improve various properties), as well as reported the first dual-phase HECs/CCCs [JECS 2020]. Using fluorite-based oxides as model systems, our recent discoveries of long- and short- range ordering, composition- and redox-induced order-disorder transitions, and ultrahigh-entropy phases in 10- to 21-component systems [Acta 2021 & 2022, Scripta 2022, JAC 2022, and many unpublished results] will be discussed as the focus of this talk.
4:40 PM
Development of Coherent Ru-based BCC + B2 Alloys with High Thermal Stability: Carolina Frey1; Haojun You1; Sebastian Kube1; Kaitlyn Mullin1; Andrew Detor2; Scott Oppenheimer2; Tresa Pollock1; 1University of California, Santa Barbara; 2GE Research
Refractory Multi-Principal Element Alloys (RMPEAs) are a new class of structural alloys for extreme environments with the potential to push operating temperatures above 1200 °C. However, the development of alloys that can operate at desired temperatures of 1300-1400 °C has been limited by a lack of strengthening precipitates that can persist at the target temperatures. Recently, HfRu-based B2 precipitates have been shown to be stable above 1200 °C. Alloys in the Hf-Mo-Nb-Ta-V-Ru system have been developed to produce alloys with coherent Ru-B2 precipitates stable at 1300 °C. A series of heat treatments between 1300-1900 °C are presented to refine the two-phase microstructure and tailor hardness. Precipitate volume fractions, sizes and spacings are evaluated. Alloys were also characterized by XRD, SEM and TEM methods. Nanopillar compression experiments were also performed to understand dislocation interactions with precipitates.
5:00 PM Invited
Deformation Behavior of CoCrFeMnNi High Entropy Alloy Highly Strained by Torsion at Elevated Temperatures: Nobuhiro Tsuji1; Reza Gholizadeh1; Shuhei Yoshida1; Yu Bai2; Shu Kurokawa1; Akinobu Shibata3; 1Kyoto University; 2Dalian University of Technology; 3National Institute for Materials Science (NIMS)
Equi-atomic CoCrFeMnNi alloy was deformed over a wide range of strains up to equivalent strains of 5.5 by torsion at various temperatures ranging from 25 °C to 1100 °C. It was found that deformation twining, which is normally absent in this alloy except for cryo-temperature deformation, was activated at moderate to high strains and even found in the deformation at temperatures as high as 600 °C. The HEA showed outstanding deformability, which was attributed to the extensive twin activities including the formation of twin bundles and thin nanotwins as well as microbands formation. A sudden shortage of ductility occurred at intermediate temperatures at 600 °C~700 °C, which was caused by the precipitation of Cr-rich σ-phases at grain boundaries.
5:20 PM Invited
Simulations and Modelling of the High Temperature Yield Behavior of Compositionally Complex Concentrated BCC Alloy: Satish Rao1; Brahim Akdim2; Oleg Senkov1; Glenn Balbus3; Eric Payton3; 1MRL Materials Resources LLC; 2UES Inc.; 3Air Force Research Laboratory
Atomistic simulations, using Johnson-Zhou and/or Snap potentials, of the core structure and mobility of ½[111] screw, edge and mixed dislocations in complex concentrated BCC alloys are presented. The core structure and its variations obtained for screw dislocations in NbTiZr using atomistic simulations are compared with first-principles calculation results and good agreement is found. Molecular Dynamics results show that a moving screw dislocation leaves behind interstitial and vacancy dipoles in these alloys. Average solute-dislocation core interaction energies are used to determine the critical stress for the motion of screw dislocations as a function of temperature using Rao- Suzuki model of kink migration / kink-kink collisions controlled mobility, developed for concentrated BCC random alloys. Edge dislocation mobilities in these alloys are modelled using the Maresca-Curtin model. The model results on yield behavior are shown to be in good agreement with experimental data in selected BCC complex concentrated alloys.