The investigation of laser shock peening effects on corrosion and hardness properties of ANSI 316L stainless steel

Laser shock peening (LSP): Electrochemical and hydrodynamic investigation of corrosion protection pre-treatment for a copper surface in 3.5 % NaCl medium

“…At LSPVC 70 % there was a decrease in the corrosion resistance which could be attributed to a mismatch of power density and the percentage overlap as the surface behaviour is dependent on the interplay of the overlap and power density inputs as shown in Table 1. This could also be attributed to an increase in local roughness as witness in this sample by the aid of SEM [8]. Fig.…”

“…The optimization of these parameters was shown in Table 1. The observed effects clearly show that power density has more impact on the surface changes than pulse overlap during the LSP process [8]. Remember that the Power density has to do with the laser energy while the pulse overlap is the number of packets of the laser light hitting the surface at a particular point in time.…”

“…The hardness of the unpeened bare Cu was 1.188 GPa, surprisingly higher than that of 40 % peened which was found to be 1.025 GPa. This could be attributed to the generation of nanoparticles and contaminants at the metal surface at the beginning of the LSP process when the laser intensity is low [8]. This shows that at low laser overlap and power density, the surface becomes poorly modified yielding surface products or pollutants of less hardness.…”

“…Several methods of surface modification techniques are in practice such as mechanical attrition, hot and cold rolling, high-pressure torsion, ball milling, mechanical shot peening, and laser shock peening to improve the surface microstructure, mechanical strength, corrosion resistance and tribological properties of the metallic material [3][4][5][6]. The surface treatment process focused on the present research is the laser shock peening (LSP) used for the improvement of corrosion protection and fatigue life of metals [7][8][9]. LSP is preferred to the rest of the processes because of its consistency in results and high-quality surface finish [10][11][12].…”

“…Consequent to the grain boundary refinement, reduction in defects such as porosity and micro-cracks were also observed, these in turn reduce the oxygen diffusivity to the metal substrate when LSP treatment is applied on the surface [9,16,17]. Mahdavi et al [8] investigated the effects of LSP on the electrochemical corrosion and microhardness properties of ANSI 316 L stainless steel alloy. Comparing the untreated and treated samples, it was found that quantitative assessment of this method for its proper application on metal corrosion protection especially where other methods such as corrosion inhibitors [29][30][31], may not be applicable.…”