Elastic energy of multi-component solid solutions and strain origins of phase stability in high-entropy alloys

SCRIPTA MATERIALIA

卷:206

Article

Kamachali, Reza Darvishi¹  Wang, Lei¹ 

[1] BAM Fed Inst Mat Res & Testing, Unter Eichen 87, D-12205 Berlin, Germany

关键词: High-entropy alloys;    Phase stability;    Phase selection;    Hume-Rothery rules;    Atomic-size effects;    Glass formation;   

DOI  :  10.1016/j.scriptamat.2021.114226

来源: Elsevier

【 摘 要 】

The elastic energy of mixing for multi-component solid solutions is derived by generalizing Eshelby's sphere-in-hole model. By surveying the dependence of the elastic energy on the chemical composition and lattice misfit, we derive a lattice strain coefficient lambda*. Studying several high-entropy alloys and super alloys, we propose that most solid solution multi-component alloys are stable when lambda* < 0 . 16 , generalizing the Hume-Rothery atomic-size rule for binary alloys. We also reveal that the polydispersity index delta , frequently used for describing strain in multi-component alloys, directly represents the elastic energy (e ) with e = q delta(2) , q being an elastic constant. Furthermore, the effects of (i) the number and (ii) the atomic size distribution of constituting elements on the phase stability of high-entropy alloys were quantified. The present derivations and discussions open for richer considerations of elastic effects in high-entropy alloys, offering immediate support for quantitative assessments of their thermodynamic properties and studying related strengthening mechanisms. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

Free