Dislocation nucleation during nanoindentation in a body-centered cubic TiZrHfNb high-entropy alloy

SCRIPTA MATERIALIA

卷:130

Article

Ye, Y. X.¹  Lu, Z. P.²  Nieh, T. G.¹ 

[1] Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA

[2] Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China

关键词: High-entropy alloy;    Nanoindentation;    Dislocation nucleation;    Activation volume and energy;   

DOI  :  10.1016/j.scriptamat.2016.11.019

来源: Elsevier

【 摘 要 】

Pop-in behavior of a single-phase, body-centered cubic TiZrHfNb high-entropy alloy was characterized using instrumented nanoindentation. The critical shear stress required for the first pop-in was close to the theoretical strength, indicating it was controlled by dislocation nucleation. Data were collected and analyzed using a model based upon the transition-state theory and Weibull statistics. The activation volume for the pop-in events was evaluated to be about 3-5 atomic volumes, much larger than that in pure metals (similar to one atomic volume), suggesting cooperative migration of multiple atoms. The activation energy was also estimated and compared favorably with the nucleation of a full-dislocation. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

Free