Influence of vacancy clusters on the atomic arrangement and displacement threshold energies in Ni3Al

Abstract

A lot of work has been done to investigate the influence of irradiation on the structure and properties of nuclear reactor materials in high irradiation for the safety and reliability. Although the point defect survival and micromechanism by irradiation are important issues, the evolution of such a region is difficult to follow experimentally, so many results are obtained from computer simulation experiments together with some purely theoretical work. Some work on the irradiation effect has been done through calculating the threshold energy for atomic displacement by computer simulation. If a displaced atom whose energy exceeds some critical or "threshold" value, Ed, causes a Frenkel pair to be produced, the displaced atom is called the primary knock-on atom (PKA) and the displacement threshold, Ed, characterizes importantly the damage irradiation. Ni3Al ordered alloy is of interest for its structure (LIZ) for threshold energy investigation and its excellent high-properties, so the threshold energy has been calculated by neutron irradiation'" 21. In this work, we adopt F-S potential modified by ~ao'~] for Ni3A1 to calculate threshold energies in typical directions, using molecular dynamics method. The results are shown in figs. 1 and 2, in which E * denotes the threshold energy without vacancy clusters. * To whom correspondence should be addressed.