|About this Abstract
||3rd World Congress on High Entropy Alloys (HEA 2023)
||Screw and Edge Dislocation Strengthening in BCC High Entropy Alloys, and Efficient Yield Strength Prediction
||Francesco Maresca, William Curtin
|On-Site Speaker (Planned)
We introduce and validate a holistic, parameter-free strengthening theory of screw and edge dislocations in BCC high entropy alloys. In contrast with screw-controlled pure BCC metals, in non-dilute BCC alloys both edge and screw dislocations are pinned due to strong local energy fluctuations. Thus, three strengthening regimes are found in screws: (1) low-temperature, Peierls-barrier controlled strength; (2) intermediate-temperature strength, due to kink migration over barriers scaling with solute/dislocation interaction; (3) high-temperature strength, scaling with energy of vacancy and self-interstitials forming after unpinning of cross-kinks. Edge dislocation strengthening scales with misfit volumes and elastic moduli. The edge theory is cast in an analytical form that is parameter-free and depends on physical quantities that can be determined ab-initio or experimentally. The reduced edge theory enables screening over 10 million compositions in the whole Al-Cr-Mo-Nb-Ta-W-V-Ti-Zr-Hf alloy family to find the strongest BCC HEAs.
||Planned: Metallurgical and Materials Transactions