A study was made of the micromechanics of dislocation loop emission, with the aim of determining the threshold condition associated with micro-void growth. A closed form for the threshold stress was obtained for an edge dislocation in the vicinity of a cylindrical void in a general planar macroscopic stress state. The effects of surface energy and lattice friction were accounted for. The former was found to be significant. A prolate-to-oblate shape transition in uniaxial strain, due to a higher driving force on a slip-plane transverse to the loading direction, was observed. In the asymptotic condition of a large void, the threshold condition was dictated by the planar mean stress for a general macroscopic stress state.

Threshold Condition of Dislocation Loop Emission from Microvoids. T.C.Tszeng: Journal of Applied Physics, 2008, 103[5], 053509