Effect of Shot Peening Exposure Time on Mechanical Behavior of Al 7075-T6 Alloy

This investigation addresses the effect of exposure time applied through shot peening as one of the severe plastic deformation technique on mechanical behavior of Al 7075-T6 alloy. Shot peening induces hardened layer in the surface region due to work-hardening effect by shot peening. The specimen shot peened for 105 s (SP105) exhibited highest values of tensile strength (591 MPa), yield strength (550 MPa) and surface hardness (265 VHN) as compared with untreated specimen with 568 MPa, 504 MPa and 184 VHN respectively. The increment in tensile properties are due to rapid improvement in the surface work-hardening by virtue of peening treatment with 105 s duration. In contrast, the shot peened alloy exhibited lower percentage elongation and higher surface roughness as compared with untreated one. The surface morphology and roughness studies before and after the treatment analyzed by suitable characterization. Besides, the extension of peening time in 140 s, the specimen lost its properties and shown lower tensile properties than 105 s peened one, even it exhibits a marginally higher hardness than SP105 specimen. As the SP140 specimen get disturbed over the longer impact of steel shots and by which the treated surface underwent into exhausted state. However, this shot peening treatment is industrially popular method due to its superior benefits compared to other surface treatments.