An atomistic study of mechanical deformation of nanostructured Ni3Al synthesized by cluster compaction

Abstract The mechanical deformation properties of nanostructured Ni 3 Al under uniaxial tensile load were studied at the atomic scale by computer modeling. The simulations were performed using a classical Molecular-Dynamics scheme based on combined Rahman–Parinello and Nose techniques with a many body interatomic potential. This potential is designed in the frame of the second moment approximation of the tight-binding model. A model sample was prepared by simulation of the compaction of isolated Ni 3 Al clusters with diameters in the range of 3.3–6.4 nm under 2 GPa external hydrostatic pressure at room temperature. After this model treatment, clusters were found to keep their identities, and their structure and segregation state did not differ much from those in the initial free clusters. Then, a uniaxial tensile stress was applied, and the strain evolution was followed as a function of time at different constant temperatures. The presence of both elastic and plastic regimes of deformation was observed, depending on the magnitude of the applied load. The Young modulus, the Poisson ratio and the elastic limit were estimated as functions of temperature. The possible intra- and inter-granular plastic deformation mechanisms are briefly discussed.