Forging and Shot-peening Contribution on Residual Stresses for a Textured Biphasic Titanium Alloy

摘要

Residual stresses are to be determined to predict mechanical behaviour of vital parts in aircraft. This part constituted by Ti-10V-2Fe-3Al is analysed using x-ray diffraction (XRD). However, the broadening and sometime the disappearance of peaks involve a major difficulty to quantify the strains and the stresses which are close to the surface. In the current study, some investigations are conducted in order to understand the difficulties to evaluate stresses by XRD. The microstructure of samples is studied by taking into account the history of surface generation: after the forging and after the shot-peening process. Shot-peening induces a distortion of the primary phase a which is close to the surface. Different deformation rates introduced by forging process have generated a different organisation in the second phase constituted by a secondary and p. To complete the investigation, crystallographic textures are performed on a phase. The main difficulty in analysing when using XRD is due to the peak broadening. The conclusion of this study identifies three separate zones beneath the surface: where the stresses can be determined, it is possible to analyze it using different method of analysis with different levels of accuracy.