[SY-C1] Symposium C-1

[SY-C1] Dislocation Motion in High Entropy Alloys

^○Luchan Zhang¹, Yang Xiang², Jian Han³, David Srolovitz³ (1.National University of Singapore, Singapore, 2.Hong Kong University of Science and Technology , Hong Kong, 3.University of Pennsylvania, United States of America)

We propose a stochastic model for dislocation motion in high entropy alloys (HEAs) that focuses on the atomic scale composition disorder. Our model is based upon how atomic-scale variations in composition effect dislocation motion through the variability of the core, rather than long range stress fields. Our model is constructed within the relatively simple Peierls-Nabarro (PN) framework, where the site occupancy disorder produces random variations in the amplitude of the interplanar potential. This in turn leads to stochastic variations in the dislocation core width, Peierls stress, and Peierls energy. Since truly random alloys are not thermodynamically stable except in the extreme high temperature limit, we also consider the effects of short range spatial correlations in the randomness. We then introduce a homogenization procedure that allows for simple incorporation of correlation. We then extend our homogenized PN results to the entire slip plane to predict the effect of randomness on the strength of the material.