Experimental evidence and molecular dynamics simulations of void growth indicated that dislocation shear loop emission was a viable mechanism of void growth. Based upon this mechanism, a theoretical model to describe the growth of nanovoid at triple junction of nanocrystalline metal under equal biaxial remote stress was suggested. In this model, it was proposed that emission of dislocation was caused by the interaction between applied stress and image stress introduced by existing nanovoids. The critical stress was derived for emission of dislocation by considering the effects of surface stress. Within the present description, dislocations emitted from surface of nanovoid were stopped at grain boundaries and the stress field generated by arrested dislocations could prevent further dislocation emission. The maximum number of dislocations emitted from the surface of the nanovoid, as a representation of the nanovoid growth, was analyzed as a function of grain size.

Nanovoid Growth in Nanocrystalline Metal by Dislocation Shear Loop Emission. L.Wang, J.Zhou, Y.Liu, S.Zhang, Y.Wang, W.Xing: Materials Science and Engineering A, 2011, 528[16-17], 5428-34