Synergistic Enhancement of Toughness Properties of Ti₄₅Zr₄₀Al₅Nb₅V₅ Lightweight High-Entropy Alloy by Hot Rolling Process

In this paper, a new lightweight Ti₄₅Zr₄₀Al₅Nb₅V₅ high-entropy alloy with a density of 5.6 g/cm³ was prepared, and the effects of hot rolling temperature on the microstructure and mechanical properties of the alloy were investigated. Starting from enhancing the strong toughness of the alloy, different hot rolling temperatures were used to roll the Ti₄₅Zr₄₀Al₅Nb₅V₅ alloy. The phase structure, microstructure and tensile mechanical properties of the alloy were also determined for the same 40% deformation (thickness changed from 22 mm to 13.2 mm) at a hot rolling temperature of 700℃~1000℃. The results show that the Ti₄₅Zr₄₀Al₅Nb₅V₅ alloy always maintains a single-phase BCC structure after hot rolling, and the grain size decreases by 25.6%~53.7%, and the tensile strength increases and then decreases with the hot rolling temperature, and the elongation increases continuously. The optimum hot rolling temperature is 800℃, at which time the alloy has an average grain size of 202 μm, a tensile yield strength of 917 MPa and a ductility of 11.3%. Grain refinement and dislocation strengthening are the fundamental reasons for the improvement of its performance, which is expected to provide a theoretical basis for the research and development of high-strength and toughened lightweight metallic structural materials.