The typical manners of dynamic crack propagation along the metal/ceramics interfaces: A molecular dynamics study

Abstract

This paper addresses the issue of crack propagation mechanisms of various interfaces using molecular dynamics (MD) simulations. Four different interfacial crack propagation behaviors are identified: (1) the strictly interfacial crack propagation (type I); (2) the crack tip blunts due to the nucleation of a twinning at the crack tip (type II); (3) crack propagates with daughter cracks ahead of the mother crack coalescing to the mother crack (type III); (4) the stacking fault nucleation appears at the crack tip and leads to the crack tip blunting (type IV). Furthermore, the adhesive strength coefficient λ is used to identify the type of the interface. A transition zone around λ=0.9 is found. Interface with λ beyond the transition zone means a “nearly clear interface”, where interfacial crack propagates in type I or type II. While the interfaces with λ below this zone are shown to be a “relative rough interface”, then type III and IV of the interfacial cracks are preferred in them. The effect of adhesive strength of interface on the mechanism of crack propagation along the interface of metal/ceramics nanocomposites is illustrated in detail. Our work can be used to actively control and design the high performance nanocomposites.