Strengthening effect of laser shock peening on 7075-T6 aviation aluminum alloy

Abstract

The strengthening effect and uniformity of residual stress and strain of 7075-T6 aviation aluminum after laser shock peening were investigated. The finite element simulation model of laser shot peening on 7075-T6 aviation aluminum alloy was established and verified. On this basis and combined with experiment, the microstructure, residual stress distribution and equivalent strain distribution of 7075-T6 aviation aluminum alloy after laser shock peening were studied. An index U for evaluating the strain uniformity in the peened area was proposed based on the statistical processing of the equivalent strain distribution in the peened area. The results show that the average grain size on the peened surface of the specimen was refined to 20–30 μm after LSP, and a residual compressive stress layer with thickness of about 0.5 mm was induced on the surface. Grain refinement and residual compressive stress can promote the strength and fatigue properties of 7075-T6 aviation aluminum alloy. The minimum value of U is obtained in the 6 × 6 spot array (the corresponding overlap ratio is 58%), which suggest that the most uniform deformation peened area can be obtained by using 58% overlap ratio in the laser shot peening process, which can avoid stress concentration and improve fatigue life.

Influence of normal load frequency on fretting fatigue behaviour by a critical plane-based approach

“…Both material fatigue properties and grain size were not investigated in the above experimental campaign. They have been found in the literature for a similar Al 7075-T6 [55][56][57]: more precisely, the microstructure consists of long strip grain, with average dimensions equal to about 100μm and 30μm in the longitudinal and transversal directions, respectively. Therefore, an average grain size equal to 55μm has been computed as the radius of the circle equivalent to the ellipse having axes equal to the material grain dimensions along the two orthogonal directions [58].…”

Effect of laser shock peening on the retention ability of surface roughness in forged Cr5 steel

“…Laser shock peening (LSP) is a recently developed surface treatment technique that has been successfully applied to improve the wear resistance and fatigue performance of metals. 12,13 During an LSP process, a shock wave with high-amplitude pressure is generated and propagates into the target material, resulting in plastic deformation and deep compressive residual stress in the surficial region. 14,15 The research focus of extensive studies was on the improvement of the wear resistance of materials after LSP.…”

Finite-element simulation of residual stresses induced by laser shock peening in TC4 samples structurally similar to a turbine blade

“…The compressive residual stress generated by LSP can reach high amplitude of about ̴ 1 GPa and extend into material up to depth of several millimeters [4]. Besides, laser shots only slightly disturb surface roughness [5], but noticeably improve surface hardness [6,7].…”