The Research on Superplasticity of Two New Ti Alloys
The superplastic tensile deformation behavior and structural evolution of two kinds of α+β titanium alloys were investigated in this paper, one is a new high strength high toughness Ti alloy with damage tolerance called TC21, and the other is a new superplastic Ti alloy so called Ti-SP2500. The results indicated that TC21 alloy has good superplasticity at the temperature from 720 to 960 and with the strain rate of 5.510-5s-1∼1.110-2s-1. On the optimal superplastic condition, the maximum elongation is over 1300%. During the superplastic tensile deformation, the dynamic recrystallization occurs in deformation zone of the specimens and the superplasticity is improved. Ti-SP2500 alloy has good superplasticity at the temperature from 720°C to 800°C and with the strain rate of 6.67 10-4s-1∼1.1110-2s-1. The maximum elongation for Ti-SP2500 alloy will exceed 2200% at 780°C with the strain rate of 5.5610-3s-1. Its superplastic deformation mechanism is controlled by grain boundary sliding, and the grain deformation and dislocation creep has the coordinating action.
Y. Q. Zhao et al., "The Research on Superplasticity of Two New Ti Alloys", Materials Science Forum, Vols. 551-552, pp. 405-410, 2007