Effect of Annealing Temperature on Microstructure and Properties of Ti-6Al-4V-2Mo-2Fe Titanium Alloy

Annealing treatment with different temperatures are performed on Ti-6Al-4V-2Mo-2Fe titanium alloy, and the effects of annealing temperatures on the microstructure and properties of the alloy are investigated. The results show that when the annealing temperature is within the range of 700 ℃ to 800 ℃, the mass fraction of primary α phase slightly decreases with the raise of the temperature, and the elongated primary α laths in the β matrix gradually redissolve, resulting in a slight decrease of the room temperature strength of the alloy, therefore the plasticity and toughness decrease significantly. Besides, needle-like secondary α phase is precipitated in the cause of cooling process. As a result, the strength of alloys is promoted significantly, and the the plasticity and toughness decrease further. When the heat treatment process is 850 ℃/2 h+air cooling, strength-plasticity-toughness combination is the beat.