Quantitative analysis on microstructure evolution of Ti-6Al-2Zr-2Sn-2Mo-1.5Cr-2Nb alloy during isothermal compression

Isothermal compression tests of Ti-6Al-2Zr-2Sn-2Mo-1.5Cr-2Nb alloy were conducted at a Gleeble-1500 simulator in deformation temperature range of 1103–1243 K, strain rate range of 0.01–5.00 s⁻¹ and height reduction range of 50 %–70 %. The effects of processing parameters on morphology, grain size and contents of α and β phases were discussed based on the quantitative microstructure examination, and the detailed explanation was shown. The results show that β transformed matrix will obviously grow up at higher deformation temperature or lower strain rate because of low grain growth activation energies. The content of α phase will decrease at higher deformation temperature or higher strain rate due to the phase transformation. Some elongated α or β grains exist at higher strain rate, implying that the dominant softening mechanism is dynamic recovery. The effect of height reduction on β transformed matrix is negligible, but the height reduction has some effects on the morphology of primary α phase.