激光粉末床熔融技术(LPBF)具有制备复杂结构、一体化成型等优势，拥有广阔的发展前景，但LPBF技术 制备高裂纹敏感性的镍基高温合金是一个较大的挑战。 在LPBF过程中，熔池与熔池之间合适的搭接距离对组织的致 密性和裂纹的产生至关重要。采用LPBF技术制备了Inconel939镍基高温合金，研究了不同扫描间距(50、70、90μm) 对微观组织、冶金缺陷的影响，并解释了裂纹的形成机理。结果表明，当激光功率和扫描速度分别固定在270W和 1800mm/s 时，随着扫描间距的增加，裂纹密度先减少再增加，在扫描间距为70μm时，获得了最低裂纹密度0.27mm/mm2。 因此，合适的扫描间距有助于提高材料致密性，减少裂纹的形成，而较大的扫描间距会增加缺陷和残余应力，进而增加 开裂的风险。

Laser powder bed fusion (LPBF) technology offers advantages such as the fabrication of complex structures and integrated forming, indicating great potential for future development. However, the use of LPBF technology to produce nickel-based superalloys, which are highly crack-sensitive, presents a significant challenge. During the LPBF process, the appropriate overlap distance between melt pools is critical for ensuring material density and minimizing crack formation. In this study, Inconel 939 nickel-based superalloys were fabricated via the LPBF technique. The effects of different scanning spacings (50, 70 and 90 μm) on the microstructure and metallurgical defects were investigated, and the crack formation mechanism was elucidated. The results show that with the laser power fixed at 270 W and the scanning speed at 1800 mm/s, the crack density initially decreased and then increased as the hatch distance increased. At a hatch distance of 70 μm, the lowest crack density of 0.27 mm/mm2 is achieved. Therefore, appropriate hatch distances help improve material density and reduce crack formation, whereas larger hatch distances may increase defects and residual stress, thereby raising the risk of cracks.