Effect of Laser Shock Peening on micro-structure and mechanical properties of Friction Stir Welded CuCrZr sheets

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2022-01, Vol.831, p.142238, Article 142238
• Main Authors: Sadhu, Abhijit, Sarkar, Sagar, Chattopadhyay, Angshuman, Mypati, Omkar, Pal, Surjya K., Nath, Ashish Kumar
• Format: Article
• Language: English
• Subjects: Compressive properties; Compressive strength; CuCrZr; Deformation analysis; Dislocation density; Fatigue life; Fatigue strength; Friction stir welding; Grain boundaries; Laser beam welding; Laser shock peening; Laser shock processing; Mechanical properties; Misalignment; Peening; Plastic deformation; Residual stress; Sheets; Surface treatment; Yield strength
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2021.142238

Friction stir welding (FSW) of CuCrZr sheets was performed and Laser Shock Peening (LSP) was carried out as a post-weld surface treatment. Effect of LSP on hardness, tensile and fatigue strength was investigated. Depth of compressive residual stress in base material increased from 550 μm to 700 μm when the number of LSP shots was increased from one to five. However, noticeable change in surface residual stress could not be observed which is attributed to the saturation of dislocation density or plastic deformation at the surface. An increase in yield strength up to ∼35% as well as an improvement in the fatigue life up to ∼70% after LSP could be achieved for base and FSW specimens. Increase in low angle grain boundaries after LSP indicates the increase in substructure induced by plastic deformation. A quantitative analysis using grain boundary misorientation and kernel average misorientation was used to understand microstructural changes due to the LSP and correlate it with the mechanical properties. •Laser Shock Peening (LSP) of Friction Stir welded CuCrZr was carried out.•Increase in yield strength (YS) up to ∼ 35% was achieved after LSP.•Increased shots improved YS while ultimate strength remained almost unchanged.•Depth of compressive residual stress increased with number of LSP shots.•Fatigue life improved by ∼70% after LSP treatment.