Review: Laser shock processing technique on the additive manufactured metallic alloys

Additive manufacturing (AM) is an efficient method to fabricate components with complex geometries. However, high levels of tensile residual stress generated in the near-surface layer of the fabricated components due to the high cooling rate and large thermal gradients during the AM process have limited their applications. Laser shock processing (LSP) is a novel surface-strengthening technique applied to modify the near-surface of metallic materials with the purpose of improving mechanical properties such as microhardness, residual stress, wear resistance, and fatigue performance. There are more and more investigations to report the combining manufacturing process of metallic alloys through AM and LSP. In this perspective, the fundamental mechanisms of AM and LSP were summarized in detail. The combining manufacturing process with LSP and AM was introduced from the aspect of residual stress, microhardness, fatigue performance, wear resistance, and microstructure evolution. Also, the microstructure-property relationship was discussed to explain the strengthening mechanism of AMed components by LSP. This work has important reference value and guidance significance for researchers to widespread the accepted LSP as a postprocessing method in the fields of AM.