Mechanical Properties of the Al3(TiTaZrNbHf) High Entropy Intermetallic Compound: A Molecular Dynamic Study

Abstract

Deformation mechanisms of the Al₃(TiTaZrNbHf) high entropy intermetallic compound under tensile loading were studied using molecular dynamic simulations. To this end, the site occupancy of the five constituent atoms that form the high entropy sublattice of Al₃(TiTaZrNbHf) was first determined by simulating the near-equilibrium melting/crystallization process. It is shown that nuclei of intrinsic stacking faults are formed under early plastic deformation due to dislocation nucleation and glide, which further contribute to the formation and growth of twin boundaries. Twinning and 1/6<112> Shockley partial dislocations are key components in the plastic deformation of Al₃(TiTaZrNbHf) at room and elevated temperatures, which is in good agreement with the experimental observations for D0₂₂-structured materials. The tensile strength of Al₃(TiTaZrNbHf) is 4.6 GPa at 300 K and slightly decreases to 4.34 GPa at 1000 K, highlighting the unique properties of high entropy intermetallic compounds in retaining their mechanical properties at elevated temperatures. The derived results provide grounds for understanding the atomic-scale origin of deformation mechanisms in high entropy intermetallic compounds. They also show potentials for tailoring the chemical composition of intermetallic compounds to overcome the problem of low ductility, paving the way to their industrial applications.