Molecular Dynamics on Hf-Nb-Ta-Ti-Zr High Entropy Alloy

Classical molecular dynamics simulations were used to investigate the structure and mechanical properties in the equiatomic Hf-Nb-Ta-Ti-Zr high entropy alloy. The open-source code LAMMPS was used to generate alloys with different crystalline lattices to determine the stable structure at 300 K. Alloying elements interacted under the action of the MEAM interatomic potential. The result showed that the alloy stabilizes in body-centered cubic (BCC) structure at 300 K. However, a wide dispersion of potential energy data as a function of atomic separation suggests the coexistence of another crystalline phase. Heating tests indicated a polymorphic phase transformation from BCC to hexagonal close-packed (HCP) at temperatures around 1100 K. Uniaxial tensile tests at a rate of 1×1010 s−1 along the [001], [110], and [111] crystallographic directions in cylindrical monocrystalline bars at 300 K were conducted. The results revealed a strong anisotropy of mechanical properties. This work provides a microscopic understanding of the mechanical behavior of the multicomponent alloy and aligns with the macroscopic theory of plastic deformation of single crystals.