Interaction mechanism of an edge dislocation with a void in Fe–Ni–Cr concentrated solid-solution alloy

Abstract

The interactions of a 1/2<110>{111} edge dislocation with a void in Fe10Ni20Cr and Fe33Ni33Cr concentrated solid-solution alloys are investigated by using molecular dynamics simulation method. The edge dislocation dissociates into two shockley partial dislocations with stacking fault in both alloys. Compared to the Fe10Ni20Cr alloy, the dislocation motion becomes difficult in Fe33Ni33Cr alloy due to the big fluctuation of stacking fault energy. The obstacle strength for a void with diameter of 2 nm in Fe33Ni33Cr alloy is slightly weaker than that in Fe10Ni20Cr alloy at temperature range from 300K to 800K. It is attributed to easy vacancies migration in Fe33Ni33Cr alloy. Interestingly, a significant increase of obstacle strength for void at 900K is noted only in Fe10Ni20Cr alloy because of the transformation from void to stacking fault tetrahedra (SFT). It is found that the compress strain upon the edge dislocation glide plane promotes the transformation from void to SFT at 900K in Fe10Ni20Cr alloy. While in Fe33Ni33Cr alloy, sluggish diffusion induced by atomic-level heterogeneity suppresses the transition from void to SFT. Consequently, Fe33Ni33Cr concentrated solid-solution alloy exhibits better irradiation hardening resistance than Fe10Ni20Cr alloy, especially at high temperature.