Abstract A series of single-track selective laser melting (SLM) experiments was carried out on IN718 plates with and without a powder layer and with different laser processing parameters (power and scan velocity) and surface conditions (original surface and sand blasted surface). The impacts of the powder, laser parameters, and surface conditions on the molten pool (MP) formation in SLM were systematically investigated through characterizations of the geometry of the resolidified MP, including width, depth, and area. Clear-cut correlations between the dimensions of the MP and the parameters were deduced from the measured data, such as between width/depth of the MP and the power of the laser beam, or between the area of the MP and the laser energy density. We also show that without a powder layer, an increased roughness of the surface consistently increases the MP cross-section area, whereas it has no impact for the cases with powder layer. Finally, the occurrence of defects, such as insufficient melting, unstable MP, and porosities/keyhole effect, is investigated and linked to the SLM parameters. We propose a processing map that defines the range of laser velocity and power for a defect-free solidification of the MP and the occurrence of the different types of defects.

中文翻译：

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IN718激光选区熔化过程中粉末、激光参数和表面条件对熔池形成的影响

摘要 以不同的激光加工参数（功率和扫描速度）和表面条件（原始表面和喷砂表面）在有和没有粉末层的IN718板上进行了一系列单道选择性激光熔化（SLM）实验。通过表征重新凝固的 MP 的几何形状，包括宽度、深度和面积，系统地研究了粉末、激光参数和表面条件对 SLM 中熔池 (MP) 形成的影响。从测量数据中推导出 MP 尺寸与参数之间的明确相关性，例如 MP 的宽度/深度与激光束功率之间，或 MP 面积与激光能量密度之间。我们还表明，如果没有粉末层，表面粗糙度的增加会持续增加 MP 横截面积，而它对具有粉末层的情况没有影响。最后，研究了缺陷的发生，例如熔化不足、不稳定的 MP 和孔隙率/小孔效应，并将其与 SLM 参数相关联。我们提出了一个加工图，该图定义了 MP 无缺陷凝固的激光速度和功率范围以及不同类型缺陷的发生。