Cross-Slip from Octahedral Onto Cube Planes in Ni3Al

Abstract

Slip in Ni3Al takes place primarily upon close-packed <111> planes by the motion of paired a/2 dislocations, although slip can also be initiated upon cube planes at temperatures above 700°K (1,2). Because the antiphase boundary energy is at a minimum on <001> (3), a net reduction of energy is possible if such paired dislocations cross-slip from octahedral onto cube planes. The likelihood of this cross-slip event plays an important role in the theories on the flow stress of Ni3Al (1,2). Observations reported previously (h) demonstrate that cross-slip takes place at 1030°K. This investigation represents a more thorough exploration of its temperature range of occurrence.