Dynamic Crack Propagation in a Bi-Metallic Nanolayer

R. Mohan
North Carolina A&T State University, US

Keywords: bi-metallic nanolayer, crack propagation, molecular dynamics


This paper focuses on the computational modeling of the dynamic crack propagation in a bi-metallic nanolayer. In particular, this paper focuses on the dynamic crack propagation in Nickel and Nickel-Aluminum bimetal nanolayer under tensile and cyclic loading conditions. Atomistic modeling analysis of crack propagation in Ni single crystal indicate the crack initially growing brittle and eventually undergoing a dynamic brittle-to-ductile transition with a spontaneous proliferation of dislocations from the crack tip following a roughening of the crack surfaces. Results for Ni-Al also showed an initial brittle crack propagation with planar cleavage of bonds between the two neighboring (001) planes defined by the initial seed crack and crack surfaces getting roughened when the crack propagation speed is about one-third of the Rayleigh wave speed for the case of uniform loading. Findings from our study clearly indicate that the crack propagation in such systems is influenced by the interactions and atomic defects at the interfaces, and the associated deformation mechanisms at the nano scale. Correlations between the nano scale and continuum deformation behavior of these material systems will be presented and discussed.