High temperature tensile behavior and microstructural evolution in nano-single crystal zirconium: A molecular dynamics simulation study

Abstract

A nano-single crystal zirconium model of dimensions 150 Å (x-axis) × 150 Å (y-axis) × 300 Å (z-axis) comprising of 298,170 atoms is created and investigated in the present study. The model is subjected to uniaxial tensile test at three different temperatures of 300 K, 600 K, and 1000 K and at a strain rate of 109 s−1 along the c-axis (z-axis). Embedded atom method (EAM) interatomic potential is used for calculating the interaction between the Zr atoms. All the simulations are carried out via open source code LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). The microstructural changes are identified through the visualization tool OVITO. The results show that the yield strength decreases as the temperature increases (14.28 GPa (300 K), 11.56 GPa (600 K) 8.32 GPa (1000 K)). Yielding occurs by twinning at temperature of 300 K and 600 K. However, at 1000 K temperature double yielding behavior is observed which can be attributed to phase transformation.