Charpy impact anisotropy and the associated mechanisms in a hot-rolled Ti–6Al–3Nb–2Zr–1Mo alloy plate

Abstract

The Charpy impact absorbed energy of a hot-rolled Ti–6Al–3Nb–2Zr–1Mo alloy plate with different sampling and notching directions was investigated. Strong anisotropic variations occurred in impact absorption energies due to difference of the α phase crystal orientation and microstructural characteristics along different directions. The higher crack propagation energy of the sampling-notching direction sample (RD-ND) resulted in an impact absorption energy of approximately 2.5 times larger than that of the TD-ND, TD-RD and RD-TD samples. Based on the analysis of the α crystal orientation and the TEM microstructure after impact deformation, it was found that the higher absorption energy of the RD-ND sample was attributed to the activities of a large number of {101‾0}⟨12‾10⟩ prismatic slips and the resistance created by grain boundaries against crack propagation, which also resulted in the delamination of the impact fracture surface. Finally, the coupling effect of crystallographic texture and microstructural characteristics on the impact deformation mechanisms of the hot-rolled Ti–6Al–3Nb–2Zr–1Mo alloy was described.