Molecular dynamics simulation of CoCrFeMnNi with twin boundaries under high-speed impact

Abstract

Based on the hybrid modeling framework of atomic scale and continuum, molecular dynamics (MD) was the method to study the shock wave, elastic-plastic dual-wave, and microstructure of CoCrFeMnNi high entropy alloy (HEA) with twin boundary under high-speed impact. The interaction between dislocation and twin interfaces is significant to the plastic deformation of HEA, but research on them as initial defects is still limited. Therefore, this article simulates and analyzes the impact velocity and twin spacing and proves that HEA with twin boundaries can synergistically improve strength and flexibility by comparing the wave simulation process and variation of spalling strength between HEA with TB and crystal Ni. The simulation results show that TB affects the propagation of shock waves in HEA and provides deformation sites for the generation of dislocations. Unlike single-crystal HEA, there is a smoother impact response process, and the maximum tensile stress during the fracture stage can reach 41 GPa, which is about 34.12% higher than that of single-crystal HEA. The research results may contribute to a better understanding of HEA with TB and help apply complex load scenarios such as explosive loads.