The role of overlap region width in multi-laser powder bed fusion of Hastelloy X superalloy

During the multi-laser powder bed fusion (ML-PBF) process, quality of overlap region is essential to ensure integrity between different laser scanning areas. Here, six widths (ORWs) are selected systematically investigate effect ORWs on densification, metallurgical defects, crystalline microstructure, and mechanical performance Hastelloy X samples processed by fusion. set 0, 50, 100, 150, 200, 250 μm, respectively. With an increment in ORW, porosity gradually increases from 0.01% 7.08%. Inversely, microcracks reduced with increasing due smaller width-to-depth ratio melt pools increased degree recrystallisation. All display equivalent ultimate tensile strength ∼880 MPa, while elongations at break 3.5%−10.5% lower than that single-laser one (28.4%). The inferior ductility ascribed decreased densification regions, which adverse can be minimised when ORW 150 μm utilised. This work anticipated provide efficient reference theoretical guidance for large-size nickel-based superalloy components fabricated ML-PBF.