Flow Stress Behavior and Deformation Characteristics of Ti-22Al-25Nb Alloys at Elevated Temperature
The characteristics of deformation of an orthorhombic phase based alloy, Ti-22Al-25Nb (at%), have been studied by hot compression tests in the temperature range of 940-1150°C with the strain rates of 0.01s-1 and 0.1s-1. A flow curves typically controlled by dynamic recovery were observed in the temperature range of 1090-1150 °C for the strain rate of 0.01s-1 , while discontinuous yield phenomena was found for the strain rate of 0.1s-1. The dynamic recovery can be identified by the microstructure characteristics of the deformation specimens. At 1060°C, the temperature of beta transus, the flow curves and microstructure exhibited the same deformation charateristics as that above the beta transus. At the subtransus temperature, a long period of flow softening followed by the steady-state flow can be observed. During the hot deformation, the hard phases α2 and O elongated, subboundary produced followed by cusp formation in the elongated α2 and O phases, the equiaxed morphology phases occurred by B2 phase penetrating along the subboundaries. The softening mechanism was discussed.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
X. B. Liang et al., "Flow Stress Behavior and Deformation Characteristics of Ti-22Al-25Nb Alloys at Elevated Temperature", Materials Science Forum, Vols. 475-479, pp. 825-828, 2005