Surface integrity and fatigue analysis of shot-peening for 7055 aluminum alloy under different high-speed milling conditions

Abstract

To study the effect of different milled surfaces on shot peening surface integrity (roughness, residual stress, hardness, and microstructure), research on the change of surface integrity is carried out using the same shot peening process for different milling surfaces of 7055-T77 aluminum alloy. Surface integrity measurements, fatigue fracture analysis, and fatigue life tests are conducted to reveal the effect of surface integrity on crack initiation and fatigue life. The results show that shot peening can reduce the dispersion and instability of surface integrity brought by milling processing, although it increases the surface roughness; the maximum residual compressive stress and depth of residual stress layer increase significantly after shot peening, and the residual stress and hardening distribution are very good; larger surface roughness and irregular surface scratches of milling samples before shot peening easily lead to cracks and gouges produced on shot peening surface.

Influence of Nanocrystalline Structure on Wear and Corrosion Behavior of Al-SiC<sub>P</sub> Composite

“…SP140 specimen has the lowest COF as compared with other specimens. The enhancement in the surface integrity and microstructure by SP contributed to yield low COF value [31]. Besides, Figure 4(c) is more discernible that the treated composites are having the lowest wear rate which is attributed essentially to the NC structure and dislocation density improved by virtue of SP.…”

The influence of shot peening on the fatigue response of Ti-6Al-4V surfaces subject to different machining processes

“…This may be due to the fact that shot peening homogenised the features [38] of the machined/built surfaces (as shown in Fig. 6) and also applies enhanced local stress conditions [39]. The only exception was with WEDM, as shown in Fig.…”

Effect of cutting parameters on the residual stress distribution generated by pocket milling of 2219 aluminum alloy

“…The underlying mechanism for the residual stress variation is due to the combined effects of the mechanical and thermal deformations. 13 When the cutting time is further increased, the increased cutting temperature induces the thermal deformation which tends to produce the tensile residual stress. Therefore, the longer continuous cutting time can seriously change the pattern of the residual stress distribution and it is advised to shorten the working time by adjusting the cutting parameters in order to obtain the required compressive stress.…”

“…Wu et al 12 investigated the milling deformation of aluminum alloy using the quasi-symmetric machining method. Yao et al 13 concluded that the maximum residual compressive stress and the depth of residual stress layer increased significantly after shot peening, and the residual stress and hardening distribution are very good. In addition, Shaw 14 and Astakhov 15 found that the chip shape shows an important relationship with the mechanical and thermophysical properties of the workpiece material.…”