Atomistic understanding of incipient plasticity in BCC refractory high entropy alloys

Xiaorong Liu, Dongpeng Hua, Wan Wang, Qing Zhou, Shuo Li, Junqin Shi, Yixuan He, Haifeng Wang

科研成果: 期刊稿件文章同行评审

30 引用 (Scopus)

摘要

Understanding the incipient plastic behavior of refractory high-entropy alloys (RHEAs) is crucial for their high-temperature applications. In this study, the initial dislocation nucleation and motion mechanisms in the TaTiZrV RHEA and their dependence on temperature were investigated upon nanoindentation by molecular dynamics (MD) simulations. Compared with the high stress-driven homogeneous nucleation criterion in pure BCC metals, the Zr-V short-range orders in the RHEA facilitate preferential inhomogeneous nucleation at low stress. The local compositional fluctuation not only causes intermittent slipping of screw dislocations by the trapping-detrapping mechanism but also severely reduces the moving rate of edge dislocations. In particular, the initial dislocation nucleation in the RHEA becomes more difficult with the increasing temperature. Based on the competitive mechanism between multiple-element-induced lattice distortion and point-defect-induced lattice distortion, the reason for their excellent retained mechanical properties at high temperatures was revealed. This study would provide theoretical support for the development of RHEAs in high-temperature technological applications.

源语言英语
文章编号166058
期刊Journal of Alloys and Compounds
920
DOI
出版状态已出版 - 5 11月 2022

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