Effect of laser shock processing on residual stress and fatigue behavior of 6061-T651 aluminum alloy
(1.江苏省镇江市江苏大学江苏激光制造科技部重点实验室
2.Jiangsu Key Laboratory of Laser Manufacture of Science and Technology Ministry,Jiangsu University, Zhenjiang 212013, China)
2.Jiangsu Key Laboratory of Laser Manufacture of Science and Technology Ministry,Jiangsu University, Zhenjiang 212013, China)
Abstract: Laser shock processing is a very new technique and an emerging modern process that generates compressive stresses much deeper into the surfaces of metals or alloys. A brief parametric study of the effect of laser parameters on fatigue behavior and residual stress state generated in 6061-T651 alloy specimens was summarized. Residual stress of 6061-T651 alloy was analyzed both before and after laser processing with multishocks. The material remains in compressive residual stress of approximate 1mm in depth which is approximately 10 times deeper than that can be achieved with the conventional technique, and the maximal compressive residual stress at the surface of the sample is about –350MPa. Near the surface, yield strength and hardness are found to be increased by the laser shock. The ratio of fatigue crack initiation life for the laser-shocked to unshocked specimens is found to be 4.9 for specimens. The results clearly show that LSP is an effective surface treatment technique for improving the fatigue performance of aluminum alloys.
Key words: laser shock processing; 6061-T651 alloy; residual stress; fatigue behavior