Abstract An investigation was conducted to understand how different parameters, namely laser power, scan speed and hatch spacing, influence the printing qualities, i.e. surface roughness, porosity and crack density of the nickel-based superalloy Inconel 738LC during laser powder bed fusion. Insufficient overlap, Plateau–Rayleigh instability and Marangoni convection were identified and characterized as the factors that could deteriorate the surface quality of as-built IN738LC parts. Two leading causes of pore were determined by metallographic analysis and computed tomography as lack of fusion and keyhole, which were attributed to different energy input densities. Crack density was measured by metallographic observation. Residual stress and the time for solidification of melt were identified as the key factors that affected the crack density. Finally, the relationships between the printing qualities and volume energy density were established by regression analysis, and the VED of ∼ 48 J/mm3 was optimal for fabricating IN738LC in the LPBF process

中文翻译：

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加工参数对激光粉末床熔融制造的 IN738LC 零件表面粗糙度、孔隙率和裂纹的影响

摘要 研究了不同参数，即激光功率、扫描速度和孵化间距，如何影响激光粉末床熔融过程中镍基高温合金Inconel 738LC 的打印质量，即表面粗糙度、孔隙率和裂纹密度。重叠不足、Plateau-Rayleigh 不稳定性和 Marangoni 对流被确定并表征为可能导致 IN738LC 部件表面质量恶化的因素。金相分析和计算机断层扫描确定了导致孔隙的两个主要原因，即缺乏融合和小孔，这归因于不同的能量输入密度。通过金相观察测量裂纹密度。残余应力和熔体凝固时间被确定为影响裂纹密度的关键因素。