Surface Properties of AA7075 Aluminium Alloy Shot Peened under Different Peening Parameters

摘要

AA7075aluminium alloy was shot peened with different size stainless steel shots atdifferent peening pressures while focusing on investigating the surfaceproperties of AA7075 alloy such as surface morphology, topography, androughness. Since shot peening (SP) is an important mechanical surface treatmentwhich leads to the local plastic deformation in the surface and sub-surfaceregions and eventually affects surface properties, the present study aims toclarify the effects of SP parameters on the surface properties of AA7075 T6 alloy.A custom-design SP system was used to shot peen the alloy by stainless steelshots with size of 0.1-0.3 mm and 0.4-0.9 mm at peening pressures of 2 bar and4 bar. The surface properties depending on shot size and peening pressure wereinvestigated by a scanning electron microscope (SEM) equipped with energydispersive X-Ray spectroscopy (EDX) and a 3D optical profilometer. The surfacemorphology affected by both parameters; larger shots and higher pressurescaused higher plastic deformation, which led to the formation of more complexand rough surfaces in comparison to the surfaces shot peened with smaller shotsat lower pressures. 3D surface topographies were visualized the deformation,which revealed the effects of shot size and pressure. The surface roughnessincreased with increases in both particles size and pressure, which causedhighly deformed and rough surface topographies with a great number of dimples.Embedding of fragmented shot particles occurred during peening.