Simulation of atomic displacement cascades in the binary alloy Zr-1%Nb near symmetrical tilt grain boundaries by molecular dynamics method

Abstract

ABSTRACTThe atomic displacement cascades simulation near symmetrical tilt grain boundaries (GBs) in binary alloy Zr-1%Nb was considered in this paper. Three symmetrical tilt GBs: , with the axis of rotation and with the axis of rotation were considered. Further defect structure analysis in modeling crystallite was conducted. For atomic displacement cascades simulation, we used molecular dynamics method and two different interatomic potentials. A tendency of the point defects produced in the cascade to accumulate near the GB plane, which was an obstacle to the spread of the cascade, was discovered. The results of the point defects’ clustering produced in the cascade were obtained. Clusters of vacancies and self-interstitial atoms were represented mainly by single point defects for both potentials. Vacancies formed clusters of a large size (more than 20 vacancies per cluster) for both potentials. The maximal size of the interstitial cluster was less than 20 point defects and was formed only in one potential. Interstitial atom clusters were mainly small-sized. Significant Nb atoms’ proportion in interstitial configuration (single defects, interstitial dimmers and interstitial clusters) was established. It means than Nb atoms actively went out from crystallite matrix in interstitial configurations.