Atomistic simulation of local chemical order in NbTiZrMoV high entropy alloy based on a newly-developed interatomic potential

Abstract

Numerous studies have demonstrated the importance of local chemical order (LCO) in influencing the mechanical properties of high entropy alloys (HEAs). However, experimental investigation of LCO remains a challenging task. In this paper, the potential parameters for NbTiZrMoV system based on the modified embedded atom method are determined by fitting the lattice constants and formation enthalpies of various binary and ternary alloys. A comparison with the results from first-principles calculations shows that the newly-developed potential has a relatively high accuracy. A hybrid MD/MC simulation is performed using the newly-developed potential to investigate the microstructural evolution of equimolar NbTiZrMoV HEA at room temperature. The simulation results show that clustering and dispersion of different elemental pairs can occur after prolonged annealing. Additionally, the Zr-V pair is observed to form LCOs with B2 structure, which may be an early stage of the experimentally observed Laves phase. Furthermore, the simulation results reveal a relationship between LCO and lattice distortion, indicating that an increase in LCO can lead to a decrease in lattice distortion, which is a significant factor in the investigation of HEA mechanical properties.