Numerical and Experimental Investigations on the Effect of Shot Peening Intensity on the Surface Integrity of TA15 Titanium Alloy Profiles

Abstract:

The effect of the shot peening intensity on the surface integrity of TA15 titanium alloy hot extruded profile was numerically and experimentally studied. The surface roughness and residual stress distribution obtained by the numerical simulation were compared with the shot peening experimental results, and the reliability of the established finite element model was verified. The effects of shot peening intensity on the microhardness and microstructure of the material surface were investigated. The experimental results show that the compressive residual stress layer with a maximum value of 558~764 MPa and a depth of 115~151 μm was introduced into the surface of TA15 titanium alloy profile after shot peening. The plastic deformation occurs on the material surface, the grain is refined, the dislocation density and the hardness of the material surface increase. The hardened layer with a depth of 100~150 μm forms, and the surface roughness increases. The increase of the shot peening intensity increases the maximum compressive residual stress, the depth of the compressive residual stress layer and the surface hardness. However, the increase is not obvious when the intensity exceeds 0.188 mmA, and the cracks might appear on the material surface. Moreover, at the intensity of 0.222 mmA, the residual stress relaxation occurs on the material surface due to the folding defect, which reduces the surface integrity of the material.

Key words:titanium alloy;profile;shot peening;numerical simulation;surface integrity