A study on the effect of various process parameters on low pulsed energy of laser shock peening without ablative layer on the mechanical behavior of AA 7075 T651

Abstract

Laser shock peening is a well-known surface treatment process that dominates other modern surface treatment processes. Though several materials are investigated to enhance mechanical properties by LSP treatment, only a scarce number of studies have concentrated on Low Pulsed Laser Shock Peening (LPLSP) without an ablative layer on Aluminum Alloy 7075 T651 material. Thus this article investigates the optimization and effect of LPLSP on the mechanical behavior of AA 7075 T651. Grey Relational Analysis is chosen to optimize the Process Parameters on Low Pulsed Energy of LSP. The significant contributions of the optimized parameters on the mechanical behavior such as hardness, compressive residual stress, roughness and friction wear property are investigated. A drastic improvementof three times in the average hardness value occurred in LPLSP over the un-peened specimen. A maximum compressive residual stress is observed with the LPLSP specimen for the optimized parameters. An improvement of 65% in the minimum wear rate was recorded in LPLSP compared to unpeened specimens. The microstructural studies carried outusing an optical microscope and scanning electron microscope show a typical grain refinement and increase in the boundary for LPLSP specimen.