Microstructural evolution and mechanical properties of oil jet peened aluminium alloy, AA6063-T6

Enhancing surface layer properties of an aircraft aluminum alloy by shot peening using response surface methodology

“…They showed that compressive residual stress grows according to shot velocity up to approximately 67 m/s, and the growth rate reduces to a minimum above this threshold velocity. Prakash et al [9] examined the hardness and compressive residual stress of oil jet peened aluminum alloy, and found that oil jet peening process introduced both the compressive residual stress and significant surface hardening. Zhan et al [10] pre-stress state on surface layer characteristic of S30432 austenitic stainless steel in shot peening process.…”

Residual stress near single shot peening impingements determined by nanoindentation and numerical simulations

“…Nanoindentation is an indentation test that has commonly been used for probing the local hardness at small length scales on a smooth surface that has undergone metallographic preparation [8][9][10][11][12]. The measured hardness is a function of two variables: the load applied to the indenter and the contact area between the sample material and the indenter [13,14].…”

Fretting wear behavior of fine grain structured aluminium alloy formed by oil jet peening process under dry sliding condition

“…The samples were oil jet peened at different transverse nozzle traveling velocities, 0.5 and 2 mm/s to attain different peening intensity. As the nozzle traveling velocity varies, the time of exposure of the target [7,10]. The oil used for peening is anti-wear hydraulic oil grade, ISO VG 68.…”

“…Peening at lower nozzle traveling velocity resulted in higher depth of hardened layer with high hardness, finer grain size and high magnitude of compressive residual stress at the surface, due to the occurrence of more number of multiple impacts [10]. The characterized microstructural features of the grain refinement process in the oil jet peened aluminium samples are the formation of ultrafine grains with randomly oriented constitute grains, submicron sized grains, high density dislocation, dislocation pile-up at the grain boundaries and localized multiple shear bands along the depth of the sample [10]. The average grain size determined by X-ray diffraction analysis and transmission electron microscopy, centreline average surface roughness (R a ), indentation surface hardness and surface compressive residual stress induced on the oil jet peened samples at different nozzle traveling velocities, 0.5 and 2 mm/s are shown in Table 3.…”

“…Increasing the surface strength of the metallic materials by application of surface modification methods is expected to be the unique solution to improve the resistance against fretting and dry sliding wear behavior [6,7]. Surface strengthening can be achieved by severe surface deformation processes such as shot peening, water jet peening, laser shock peening, deep rolling, low plasticity burnishing, oil jet peening, controlled ball impact peening and ultrasonic shot peening Oil jet peening, a new surface enhancement technique is developed for inducing compressive residual stresses on the surface of the metallic materials along with the formation of ultrafine grain structure at the surface [8][9][10]. The presence of surface compressive residual stresses reduce the possibility of a propagating fatigue crack by decreasing the peak applied tensile stress.…”