Amorphization and order-disorder in Ni-Al system under high energy ion-irradiation:: A computer simulation study

Starting from the dispalcement cascades, as obtained using the binary collision approximation, we derive the spatial distribution of the energy deposited into the lattice by the primary knock-on atom (PKA). We follow the time evolution of the cascade core in two ordered intermetallics Ni3Al and NiAl, using molecular dynamics (MD) technique with the embedded potential and with the liquid droplet model (LDM), in which a simplified version of the heat equation is solved. Moreover,the MD method was used to determine the evolution of the local structure to identify the disordered zones which can be compared to the transmission electron microscope (TEM) observations up to a PKA energy of 15 keV. The LDM allows us, after a calibration with MD results, to estimate the dependence of the molten volume on the PKA energy up to 1 MeV. The results are in good agreement with other published simulations and experiments.