Dynamic Crack Propagation in a Bi-Metallic Nanolayer

R Mohan and Y Purohit, NANOTECHNOLOGY 2012, VOL 2: ELECTRONICS, DEVICES, FABRICATION, MEMS, FLUIDICS AND COMPUTATIONAL, 661-664 (2012).

Deformation behaviors of nanoscale metallic systems under mechanical loading conditions have received considerable attention in the recent years. Associated with mechanical deformation of the material systems are their fracture and failure. 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 arid Nickel Aluminum bi-metal 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. 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.

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