Residual stress and microhardness evolution induced by conventional and ultrasonic shot peening

Abstract

Very limited comparative research has been conducted on microstructure evolution induced by different peening methods. Herein, the 2024T351 aluminium alloy was subjected to conventional shot peening (CSP) and ultrasonic shot peening (USP) under the identical Almen height to investigate the differences in surface roughness, residual stress and microhardness. The results demonstrated that under the same Almen height, the CSP treatment resulted in a rougher surface with higher surface roughness and more surface defects, and higher surface and maximum compressive residual stress (CRS) than the USP treatment. In contrast, the CRS depth was relatively lower for the CSP treated samples. In addition, the USP treatment produced more significant microhardness and hardened layer than the CSP treatment.

Microstructures and properties of ultrasonically surface-modified Cu–0.2Be–1.0Co alloy

“…The high frequency impact can induce plastic deformation and compress residual stress in the metal surface layer, which will generate gradient grain refinement microstructures as well as dense dislocations and consequently lead to surface strengthening [21,22]. Compared with other surface plastic deformation methods, such as high-pressure torsion [23], singleroll angular-rolling [24], laser shock peening and ultrasonic shot peening [25][26][27], USM exhibits precise controllability, complex geometric processing capability, less surface deterioration, high work efficiency, low cost and easy operability [28][29][30].…”