Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy:an atomistic simulation study  

作　　者：Won-Mi Choi Yong Hee Jo Seok Su Sohn Sunghak Lee Byeong-Joo Lee 

机构地区：[1]Department of Material Science and Engineering,Pohang University of Science and Technology(POSTECH),Pohang 37673,Republic of Korea

出　　处：《npj Computational Materials》2018年第1期662-670,共9页计算材料学（英文）

基　　金：This research was supported by the Future Material Discovery Program of the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT of Korea(2016M3D1A1023383).

摘　　要：Although high-entropy alloys(HEAs)are attracting interest,the physical metallurgical mechanisms related to their properties have mostly not been clarified,and this limits wider industrial applications,in addition to the high alloy costs.We clarify the physical metallurgical reasons for the materials phenomena(sluggish diffusion and micro-twining at cryogenic temperatures)and investigate the effect of individual elements on solid solution hardening for the equiatomic CoCrFeMnNi HEA based on atomistic simulations(Monte Carlo,molecular dynamics and molecular statics).A significant number of stable vacant lattice sites with high migration energy barriers exists and is thought to cause the sluggish diffusion.We predict that the hexagonal close-packed(hcp)structure is more stable than the face-centered cubic(fcc)structure at 0 K,which we propose as the fundamental reason for the micro-twinning at cryogenic temperatures.The alloying effect on the critical resolved shear stress(CRSS)is well predicted by the atomistic simulation,used for a design of non-equiatomic fcc HEAs with improved strength,and is experimentally verified.This study demonstrates the applicability of the proposed atomistic approach combined with a thermodynamic calculation technique to a computational design of advanced HEAs.

关 键 词：ALLOY ALLOYING ENTROPY 

分 类 号：TG1[金属学及工艺—金属学]