Evolution of texture and residual stresses after laser shock peening in titanium alloys VT6 and VT1-0

Abstract

The paper investigates the effect of laser shock peening (LSP) on the evolution of the crystallographic texture and residual stresses of titanium alloys VT1-0 and VT6. The research purpose was to study changes in the X-ray spectrum and texture before and after LSP with the use of X-ray diffraction and MTEX software package for analyzing complete pole figures. The samples were subjected to laser treatment with the following parameters: wavelength – 1064 nm, pulse energy – 1 J, pulse duration – 10 ns. The results have shown that the texture of VT1-0 alloy is characterized by heterogeneity. A gradient of maximum pole density is observed, which increases from 2.6 in the central part of the leaf to 3.2 in its marginal zone. After LSP, there was noted a decrease in the texture sharpness at the edge of the leaf (mrd decreased to 2.6), while in the center the changes were insignificant. For VT6 alloy, the texture turned out to be initially weak (mrd ≈ 1.3), and LSP did not cause its noticeable transformation. It is shown that the peaks of the diffraction spectrum widen for VT6 and VT1-0 alloys, which is associated with the deformation of the crystal lattice and changes in the magnitude of residual stresses.