An Experimental Study on Crack Closure Induced by Laser Peening in Pre-cracked Aluminum Alloy 2024-T351 and Fatigue Life Extension

Abstract This study investigates crack closure induced by laser peening (LP) and its effect on fatigue life extension of 2024-T351 aluminum alloy with initial fatigue crack. LP is applied directly in the initial fatigue crack region. This treatment leads to interesting observations of crack arrest that has not been reported before for LP, and significant fatigue life enhancement. The fatigue life of the LP-treated pre-crack specimen is 412% and 44.7% higher than the untreated specimen and LP-treated specimen without pre-crack, respectively. The crack closure around the pre-crack resulting from the LP-induced plastic deformation is mainly responsible for fatigue life extension.