Effects of laser power on texture evolution and mechanical properties of laser-arc hybrid additive manufacturing

Abstract

The effects of laser power on the formation, texture evolution, and mechanical properties of 316L stainless steel fabricated by laser-arc hybrid additive manufacturing were studied. The results showed that the surface accuracy was first improved and then degraded with increasing laser power, because the stability of the molten pool first rose and then fell with the rising laser power. Additionally, the microhardness decreased with the increase in deposition height, but the trend became weaker with further heat accumulation. When the laser power was amplified from 500 to 2000 W, the molten pool gradually changed from the conduction to keyhole mode (KM), and the cube texture content increased from 0% to 65.5%. A 5.5% Goss texture was generated in the KM at 2000 W, because the migration of the solid–liquid interface gradually deviated to the <011> direction. Furthermore, the KM expanded the range of the remelted zone, the number of bonding layers, and the content of grains with low misorientation angle significantly. Therefore, the ultimate tensile strength of the part produced in the KM was able to reach 600 MPa, higher than that of the conduction mode part (520–530 MPa) fabricated at a lower laser power.