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 α_p and β_tr phases, as well as the activation of multiple slip systems in the α_p phase. This project provides a hot processing for simultaneously enhancing both the strength and ductility of titanium.