Effect of heat treatment on microstructure and properties of a new low-cost Ti-5Al-1.5Mo-1.8Fe alloy

A new low-cost titanium Ti-5Al-1.5Mo-1.8Fe alloy has been developed. The different solid solution temperatures and cooling rates as well as deformations effect on microstructure and mechanical properties of this alloy were studied. The results have shown that the alloy exhibits a lamellar α + β microstructure after undergoing solid solution and aging treatment, leading to a significant increase in strength. Specifically, the alloy with forging deformation of 20% shows the highest strength after heat treatment, and the yield strength and tensile strength are 950 MPa and 1100 MPa, respectively. Moreover, different cooling rates, such as water quenching and air cooling, can yield diverse morphologies of α + β microstructures. Specifically, water quenching leads to the formation of a lamellar structure comprising acicular martensite α. Notably, the mechanical properties of this new low-cost alloy are influenced by the cooling rate. Higher strength is achieved through faster cooling rates, with the yield and tensile strengths being 1040 MPa and 1150 MPa, respectively.