Dislocation Decomposition, Dissociation, and Deformation in MoSi2 AND α-Al2Q3 Single Crystals

Abstract

The mechanisms of deformation in single crystal MoSi2 along [001] at temperatures of 900 to 1450°C are compared and contrasted with the mechanisms of deformation of single crystal α-Al2Q3 deformed by prismatic slip at temperatures of 1450-1700°C. In both cases, deformation occurs by dislocations with large Burgers vectors at lower temperatures. These dislocations are dissociated into three collinear partials separated by antiphase boundaries or stacking faults. At higher temperatures, these dislocations with large Burgers vectors decompose into two perfect dislocations. This decomposition has the effect of forcing slip on another slip system in MoSi2 and increasing the work hardening rate in α-Al2Q3.