Unusual activated processes controlling dislocation motion in body-centered-cubic high-entropy alloys

• DOI: 10.1073/pnas.1919136117
• Publication Date: 2020-06-30T00:37:55Z
• Authors: Bing Chen; Suzhi Li; Hongxiang Zong; Xiangdong Ding; Jun Sun; Evan Ma
• Keywords: Physical Sciences; 02 engineering and technology; 0210 nano-technology

Significance This work demonstrates dislocation dynamics in body-centered-cubic (BCC) high-entropy alloys (HEAs). The local composition inhomogeneity in these concentrated solutions leads to an unconventional rate-controlling mechanism that governs dislocation mobility. The activated process becomes nanoscale detrapping, of kinks on screw dislocations and of trapped segments of edge dislocations, presenting an activation barrier of similar magnitude for both dislocation types. Their sluggish mobility explains the elevated strength and strain hardening in BCC HEAs.