Effects of Heat Treatment on Microstructures and Properties of Ti811 Alloys
Mechanical properties and microstructures of Ti811 alloys under different heat treatment conditions were studied. The results show that the microstructures of Ti811 alloy consist of α, massive β and grain-boundary β after normal annealing. The intensity and hardness decreased, while the ductility increased. After double annealing, the primary phase α reduced and needle-like secondary α〞 was formed. The massive β and grain-boundary β changed into intergranular β gradually. The microstructure was relatively uniform. Then the intensity and hardness increased, the ductility decreased when compared to general annealing. The needle-like secondary α〞and metastable β would break down into dispersed α and β after solution hardening and aging. The combination properties of alloys would be improved. According to fractography of titanium alloy, the fracture mechanism of the Ti811 alloy was dissociation - brittle intergranular fracture, which was a type of fracture between the intergranular fracture of brittle and cleavage fracture.
Huixuan Zhang, Ye Han, Fuxiao Chen and Jiuba Wen
H. G. Wang et al., "Effects of Heat Treatment on Microstructures and Properties of Ti811 Alloys", Applied Mechanics and Materials, Vols. 117-119, pp. 1032-1035, 2012