Effect of Laser Power on Microstructure and Mechanical Properties of Austenitic Stainless Steel Fabricated by Laser Coaxial Powder‐Feeding Hybrid Wire Arc Additive Manufacturing

A novel laser coaxial powder‐feeding hybrid wire arc additive manufacturing (LP‐WAAM) method was proposed for ceramic particle‐reinforced wire arc additive manufacturing (WAAM). This method enables high deposition efficiency and precise process control through the formation of a shared molten pool. The results show that, under different laser powers, the droplet transfer mode remained a mixed mode of globular and short‐circuit transfer. As the laser power increased from 600 to 1200 W, the droplet transfer became increasingly stable and the macroscopic morphology of the deposited layer improved. Correspondingly, the average grain size increased from 90.27 to 121.37 μm. However, when the laser power was further increased to 1400 W, the stability of droplet transfer deteriorated and the average grain size decreased to 110.20 μm. With increasing laser power, the microhardness first decreases from 240.61 to 228.79  HV and then increases to 230.01 HV. Under the same processing conditions, the hardness of the LP‐WAAM‐fabricated specimens was approximately 11.44% higher than that of the WAAM‐fabricated specimens. Influenced by grain size and hardness, the coefficient of friction (COF) first increased from 0.133 to 0.266 and subsequently decreased to 0.198 with the increase in the laser power.