The dynamic response of the metastable β titanium alloy Ti-2Al-9.2Mo-2Fe at ambient temperature

• DOI: 10.1016/j.msea.2019.02.068
• Publication Date: 2019-02-21T22:56:19Z
• Authors: J.F. Xiao; Z.H. Nie; C.W. Tan; G. Zhou; R. Chen; M.R. Li; X.D. Yu; X.C. Zhao; S.X. Hui; W.J. Ye; Y.T. Lee
• Keywords: Split Hopkinson Pressure Bar; Deformation mechanism; Titanium alloy

Abstract The mechanical behavior of a metastable β titanium alloy, Ti-2Al-9.2Mo-2Fe (wt%), was studied through high compression strain rate (~3000 s−1) at ambient temperature by Spilt Hopkinson Pressure Bar (SHPB) tests after solution treatment at 850 ℃ for 0.5 h and 950 ℃ for 1 h. The mechanism of deformation and microstructure evolution was investigated by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Multiple deformation mechanisms, including primary and secondary {332} twinning, stress-induced martensite, and stress-induced ω-phase and dislocation slips, were identified in specimens subjected to solution treatment at 850 ℃ for 0.5 h. In contrast, only primary and secondary {332} twinning and dislocation slips were detected in specimens subjected to solution treatment at 950 ℃ for 1 h. The athermal ω precipitation produced after solution treatment and elevated temperature generated during dynamic loading played a crucial role in the different deformation mechanisms observed in the two different specimens. Moreover, the deformation mechanisms active during plastic deformation in the different strain regimes affected the development of different textures in the Ti-2Al-9.2Mo-2Fe alloys from each regime.