Void growth in single crystal Copper-an atomistic modeling and statistical analysis study

摘要

One of the failure mechanisms in ductile materials is growth and coalescence of pre-existing voids. In view of this, we attempt to obtain atomistic insights into the prevailing mechanisms of void growth in a representative ductile material, namely Copper, using molecular dynamics simulations. In addition to shedding light on the observed length scale effects and dislocation mechanisms, we also elucidate how atomistic simulations can inform continuum-based models of failure and provide fodder for bridging different length scales. By performing a series of over 150 molecular dynamics simulations, we also try to decode the interplay between mechanical properties and void growth, and investigate the role of heterogeneity in void distribution (in terms of void size and placement) in affecting the strength of the material. Coupled with a comprehensive global sensitivity analysis technique, we explore configuration-property relationships in a subset of vast parameter space and highlight the importance of random nature of void distribution (along with some critical statistical parameters) in any successful theory of fracture.