The influence of heat processing on the microstructure and properties of a high-strength titanium alloy

Strength and ductility are important indicators for evaluating the performance of titanium alloys. However, the “strength-ductility trade-off” issue significantly restricts the engineering applications of titanium alloys. In this project, the Ti-1500 alloy was selected as the research subject. Through a thermomechanical process that combines rolling and drawing, a bimodal microstructure was successfully fabricated. The strength and ductility of the Ti-1500 alloy were both improved through the drawing process, reaching 1600 MPa and 11 %, respectively. It is noteworthy that the grains of the Ti-1500 alloy were further refined through the drawing. Additionally, a strong fiber texture with 〈0 0 0 1〉//RD was formed in the α phase of the Ti-1500 alloy by drawing. This texture increased the critical resolved shear stress required for the activation of slip systems in the α phase. These factors collectively contributed to the enhancement of the yield strength of the Ti-1500 alloy. Meanwhile, the enhancement in the ductility of the alloy by drawing is primarily attributed to the improved coordinated deformation capability between the αp and βtr phases, as well as the activation of multiple slip systems in the αp phase. This project provides a hot processing for simultaneously enhancing both the strength and ductility of titanium.