Effect of annealing temperature on the microstructure and mechanical properties of Al15Ti35V20Nb15Zr15 alloy

In this study, the effects of annealing temperature on the microstructure and mechanical properties of Al₁₅Ti₃₅V₂₀Nb₁₅Zr₁₅ lightweight high-entropy alloy were systematically investigated. Results indicate that the Al₁₅Ti₃₅V₂₀Nb₁₅Zr₁₅ alloy exhibits a dual-phase structure consisting of body-centered cubic (BCC) and hexagonal close-packed (HCP) phases. As the annealing temperature increases, the HCP phase grows along the grain boundaries, accompanied with the precipitation of a needle-like phase. The alloy primarily demonstrates a dendritic structure, and the rise in annealing temperature promotes dendrite refinement, reducing the grain size from approximately 227.21 μm to 88.28 μm. This refinement remarkably enhances the alloy's strength, hardness, and wear resistance. The yield strength of the alloy increases from ∼1718 MPa to ∼1941 MPa with the increase of annealing temperature. However, this enhancement partially affects plasticity primarily because of the precipitation of acicular phases, which hinders dislocation motion and the increase in internal stress within the alloy, thereby leading to reduced ductility.