Improvement of the grain structure and mechanical properties of austenitic stainless steel fabricated by laser and wire additive manufacturing assisted with ultrasonic vibration

Abstract The ER321 stainless steel was fabricated by laser and wire additive manufacturing (LWAM) assisted with ultrasonic vibration (UV) under synchronous motion conditions. It was found that the grain structure of ER321 stainless steel varied from coarse columnar dendrites (without UV) to equiaxed dendrites (with UV). And, the UV effectively weakened the texture strength and homogenized the grain structure of the deposition layers. The improvement of grain structure enhanced the microhardness (~10.7%) and yield strength (~11.9%) of ER321 stainless steel. These results show that this innovative manufacturing approach can effectively improve the problem of coarse columnar dendrites in the additive manufactured complex large-scale components.