Size-dependent deformation in nanograins and nanotwins

摘要

This paper discusses three aspects that have not been looked into within mechanistic model for rationalizing observed behavior of nanocrystalline materials. (1) For the nano-materials with low energy barrier to emit the trailing partial after the leading partial, such as nanocrystalline Al (nc-Al), both partials extend intra-granularly in strengthening effect. (2) In the transition grain-size region between strengthening and softening, the coupled effect of intra-granular dislocation extension and grain boundary deformation contributes to flow stress. (3) Reformulating the non-homogeneous nucleation model, the activation volume is further examined.