ICME 2023: App: Alloy Des. I
Program Organizers: Charles Ward, AFRL/RXM; Heather Murdoch, U.S. Army Research Laboratory
Tuesday 10:10 AM
May 23, 2023
Room: Boca I-III
Location: Caribe Royale
Session Chair: Paul Mason, Thermo-Calc Software Inc.
10:10 AM
Rapid Design of High-performance Refractory High Entropy Alloys Aided by Multiscale Modeling and Additive Manufacturing: Michael Gao1; David Alman1; Saro San1; William Trehern1; Chantal Sudbrack1; Paul Jablonski1; Vishnu Raghuraman2; Mike Widom2; Saket Thapliyal3; Michael Kirka3; 1National Energy Technology Laboratory; 2Carnegie Mellon University; 3Oak Ridge National Laboratory
The main challenges in developing next-generation refractory alloys for ultrahigh-temperature service beyond nickel-base superalloys are balancing room temperature ductility & fracture toughness, and high temperature strength and creep resistance, while maintaining comparable oxidation resistance and densities to Ni-base superalloys. This project integrates multi-scale computational modeling with direct energy deposition additive manufacturing to rapidly design precipitation strengthened refractory high entropy alloy for use at 1300 degree Celsius and above. Specifically, high throughput phase diagram calculations and screening are carried out using CALPHAD; density functional theory calculations are performed to predict intrinsic ductility, grain boundary segregation energy, coefficient of thermal expansion and temperature-dependent elastic constants. Down-selected alloys are synthesized in small buttons of about 250g using arc melting for rapid evaluation on microstructure and mechanical properties before employing plasma arc melting and additive manufacturing for producing large ingots. Preliminary computational and experimental results of this project will be presented.
10:30 AM
Automated Hierarchical Screening of Refractory Multicomponent Alloys with High Intrinsic Ductility and Surface Passivation Potency: Aditya Sundar1; Yong-Jie Hu2; Liang Qi1; 1University of Michigan; 2Drexel University
Body-centered cubic (bcc) refractory multicomponent alloys are of great interest due to their remarkable strength at high temperatures. Optimizing the chemical compositions of these alloys to achieve a combination of high strength, room-temperature ductility, and corrosion resistance remains challenging. With physics-informed descriptors and a simple bond-counting model, we developed regression models to predict the unstable stacking fault energy (γusf) and surface energy (γsurf) for BCC multicomponent alloys. Then we develop hierarchical screening models to identify promising alloys from a 13-element composition space (Ti-Zr-Hf-V-Nb-Ta-Mo-W-Re-Ru-Al-Cr-Si). We rapidly screen over ~10 million quaternary alloys using our regression models to search for alloy candidates that may have enhanced strength-ductile synergies. The results combined with high-throughput thermodynamics calculations are used to discover ~1000 promising bcc refractory alloy compositions with potentially high ductility potency, the thermodynamic stability of single bcc phase at least at 800 C, and the thermodynamic capability to passive oxide films.
10:50 AM
Examining Phonon Transport in High Entropy Oxides: An Advanced Thermal Barrier Coating Material: Prince Sharma1; Ganesh Balasubramanian1; 1Lehigh University
Thermal Barrier Coating (TBC) material are used to protect gas turbine blades from high temperatures. Yttria-Stabilized Zirconia (YSZ) is widely used TBC material with a maximum operational temperature of 1600 K. With the ever-increasing demands of fossil fuels and its impact to environment it is crucial to design materials that can serve at ultra-high temperatures without failure to increase the efficiency of engines. In this study we present new High Entropy Oxides (HEOs) designed on the basis of first principal calculations. Phonon calculation were performed to determine thermal expansion and conductivity of the compounds. We found that these materials possess ultra-low thermal conductivity (k) and higher stability above 1600 K. Due to increased configuration entropy and high structural distortion there is enhanced phonon scattering and hence the material possess ultra-low thermal conductivity. HEOs are compared to YSZ via an assessment of phonon dispersion, phonon lifetime, group velocity and thermal conductivity.
11:10 AM
A Computational Tool For Microstructure Development In Multicomponent Alloys During Additive Manufacturing: Christopher Hareland1; Gildas Guillemot2; Charles-André Gandin2; Peter Voorhees1; Jin Zhang1; 1Northwestern University; 2Mines ParisTech Sophia Antipolis
The properties of additively manufactured materials are intimately connected to the solidification process. The interfacial velocities found during additive manufacturing can lead to interfacial nonequilibrium at the moving solid-liquid interface. A thermodynamic description of moving non-equilibrium interfaces is developed that is applicable to concentrated multicomponent alloys. We find that solute drag affects both the velocity of the interface and distribution coefficients for the compositions of the two phases at the interface. This theory has been integrated with a description of dendritic growth in multicomponent alloys that incorporates CALPHAD descriptions of the Gibbs free energies and diffusion matrices with off-diagonal diffusion coefficients. This computational tool yields morphology diagrams for the solidification morphologies of complex multicomponent alloys of industrial importance during additive manufacturing. Examples of such diagrams for alloys of commercial importance, such as stainless steel 316L, will be given.
11:30 AM
Optimizing AgAuCuPdPt High Entropy Alloy Compositions as Efficient Catalysts for CO2 Reduction Reaction: Chinmay Dahale1; Sriram Goverapet Srinivasan1; Beena Rai1; 1Tata Consultancy Services Ltd.
High entropy alloys (HEA) are emerging as superior catalysts for diverse chemical conversions. While their vast compositional and configurational degrees of freedom offer a rich platform for catalyst discovery, elemental segregation could limit the chemical diversity at the surfaces of these alloys. Building upon our recent work (Dahale et al, Mol. Syst. Des. Eng., 2022,7, 878-888), we use a combination of machine learning based adsorption energy prediction and Bayesian optimization to identify AgAuCuPdPt HEA compositions that are both active and selective for CO2 reduction reaction (CORR). We further show that, the reduction in the chemical diversity at the surface due to elemental segregation causes only a marginal change in the activity but a significant enhancement in the selectivity for CORR.