Influence of Nanotwin Generation near Crack Twins on the Fracture Toughness of Nanomaterials

摘要

A theoretical model of microscopic mechanisms of the nucleation and development of deforma- tion twins in nanocrystalline materials has been developed. Within the model, we have studied the generation of deformation twins near crack tips, which occurs through multiple nanoscopic shears that represent nano- scopic regions of an ideal plastic shear. It has been shown that the nucleation of such nanotwins near crack tips reduces the high local stresses that arise near these tips. Thus, the generation and development of nanot- wins near crack tips increases the fracture toughness of brittle nanocrystalline materials and serves as an effi- cient mechanism of improving the crack resistance of deformed nanocrystalline materials.