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 toenhance mechanical properties by LSP treatment, only a scarce number of studies have concentrated on Low Pulsed Laser Shock Peening (LPLSP) without an ablative layeron 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.

Laser Shock Peening: Fundamentals and Mechanisms of Metallic Material Wear Resistance Improvement

“…Following the application of LSP treatment, small-sized carbides are effectively joined with the matrix by the shock wave, thereby acting as a barrier against deformation and enhancing wear resistance [72]. In the region affected by the shock wave, the grain size reduces, leading to a substantial increase in the quantity of grain boundaries [73]. Additionally, LSP-treated In LSP, the high-density energy affects grain orientation and triggers grain slip, resulting in a significant number of dislocations [70].…”