Shock-induced amorphization in medium entropy alloy CoCrNi. (1st March 2022)

• Record Type: Journal Article
• Authors: Jian, Wu-Rong; Xie, Zhuocheng; Xu, Shuozhi; Yao, Xiaohu; Beyerlein, Irene J.
• Is Part Of: Scripta materialia. Number 209(2022)
• Publication Date: 2022-03-01
• Subjects: Impact behavior -- High-speed deformation -- Amorphization -- Microstructure -- Molecular dynamics; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2021.114379
• Languages: English
• ISSNs: 1359-6462

Abstract

Graphical abstract: Abstract: We perform molecular dynamics simulations to investigate shock-induced amorphization in CoCrNi, a medium entropy alloy (MEA) and its mean-field variant without lattice distortion. We show that a critical velocity exists above which amorphization occurs. At a low shock velocity of 800 m/s, dislocation slip and twins dominate and amorphization does not happen, but as the shock velocity increases, the deformation mechanism transitions from slip and twinning to solid-state amorphization. Under ultra-high shock velocities, extensive amorphization occurs, following the precursor of shock wave, eliminating anisotropy in spall strength. Compared to the mean-field model, lattice distortion in the MEA causes substantially more amorphization, resulting in a lower spall strength, since voids nucleate and grow preferentially in the amorphous regions.