Recent advances in post-processing technologies for laser additive manufacturing

Although laser additive manufacturing (LAM) has attracted widespread attention due to its design freedom and high material utilization, the metallurgical defects, high residual stress, and coarse columnar grains caused by its inherent rapid melting and solidification characteristics constrain large-scale application. This paper systematically elucidates how ultrasonic, thermal, and mechanical post-processing strategies regulate the microstructural evolution and enhance the properties of additively manufactured materials. Ultrasonic rolling and ultrasonic impact peening introduce high-frequency vibrations that induce severe surface plastic deformation, thereby simultaneously improving surface integrity, grain refinement, and compressive residual stress. Interlayer ultrasonic impact peening achieves grain refinement exceeding 94%, while ultrasonic nanocrystalline surface modification extends fatigue life by more than one order of magnitude through gradient nanostructuring. Thermal field-assisted post-processing actively reconstructs the thermal history to suppress Laves phase precipitation and elemental segregation in nickel-based superalloys, and an isotropic high-temperature, high-pressure environment increases component relative density to over 99.97%. Mechanical methods such as rolling and forging induce dynamic recrystallization through accumulated plastic strain, transforming columnar grains into equiaxed fine grains and mitigating mechanical anisotropy. Flexible techniques including magnetic abrasive finishing, electrochemical polishing, and laser polishing offer low-damage, non-contact finishing solutions for complex internal channel surfaces. Finally, this paper summarizes the current status and trends of LAM post-processing, aiming to provide a reference for high-performance LAM development.