The origins of nano-scale oxide inclusions in 316L austenitic stainless steel (SS) manufactured by laser powder bed fusion (L-PBF) was investigated by quantifying the possible intrusion pathways of oxygen contained in the precursor powder, extraneous oxygen from the process environment during laser processing, and moisture contamination during powder handling and storage. When processing the fresh, as-received powder in a well-controlled environment, the oxide inclusions contained in the precursor powder were the primary contributors to the formation of nano-scale oxides in the final additive manufactured (AM) product. These oxide inclusions were found to be enriched with oxygen getter elements like Si and Mn. By controlling the extraneous oxygen level in the process environment, the oxygen level in AM produced parts was found to increase with the extraneous oxygen level. The intrusion pathway of this extra oxygen was found to be dominated by the incorporation of spatter particles into the build during processing. Moisture induced oxidation during powder storage was also found to result in a higher oxide density in the AM produced parts. SS 316L powder free of Si and Mn oxygen getters was processed in a well-controlled environment and resulted in a similar level of oxygen intrusion. Microhardness testing indicated that the oxide volume fraction increase from extraneous oxygen did not influence hardness values. However, a marked decrease in hardness was found for the humidified and Si-Mn free AM processed parts.

通过量化前驱粉末中所含氧气，工艺过程中来自加工环境的外​​来氧气的可能侵入途径，研究了通过激光粉末床熔合（L-PBF）制造的316L奥氏体不锈钢（SS）中纳米级氧化物夹杂物的起源。激光加工，以及粉末处理和储存期间的水分污染。在良好控制的环境中加工新鲜的，接收的粉末时，前体粉末中包含的氧化物夹杂物是最终制造的添加剂（AM）产品中形成纳米级氧化物的主要因素。发现这些氧化物夹杂物富含诸如Si和Mn的吸气剂元素。通过控制过程环境中的多余氧气含量，发现AM生产的零件中的氧气含量会随着外部氧气含量的增加而增加。发现这种多余的氧气的入侵途径主要是在加工过程中将飞溅粒子掺入到构件中。还发现在粉末存储过程中水分引起的氧化会导致AM生产部件中较高的氧化物密度。在良好控制的环境中对不含Si和Mn吸气剂的SS 316L粉末进行了处理，并导致相似程度的氧气侵入。显微硬度测试表明，来自外部氧气的氧化物体积分数增加不会影响硬度值。但是，对于加湿和无Si-Mn的AM加工零件，发现硬度明显降低。发现这种多余的氧气的入侵途径主要是在加工过程中将飞溅粒子掺入到构件中。还发现在粉末存储过程中水分引起的氧化会导致AM生产部件中较高的氧化物密度。在良好控制的环境中对不含Si和Mn吸气剂的SS 316L粉末进行了处理，并导致相似程度的氧气侵入。显微硬度测试表明，来自外部氧气的氧化物体积分数增加不会影响硬度值。但是，对于加湿和无Si-Mn的AM加工零件，发现硬度明显降低。发现这种多余的氧气的入侵途径主要是在加工过程中将飞溅粒子掺入到构件中。还发现在粉末存储过程中水分引起的氧化会导致AM生产部件中较高的氧化物密度。在良好控制的环境中对不含Si和Mn吸气剂的SS 316L粉末进行了处理，并导致相似程度的氧气侵入。显微硬度测试表明，来自外部氧气的氧化物体积分数增加不会影响硬度值。但是，对于加湿和无Si-Mn的AM加工零件，发现硬度明显降低。在良好控制的环境中对不含Si和Mn吸气剂的SS 316L粉末进行了处理，并导致相似程度的氧气侵入。显微硬度测试表明，来自外部氧气的氧化物体积分数增加不会影响硬度值。但是，对于加湿和无Si-Mn的AM加工零件，发现硬度明显降低。在良好控制的环境中对不含Si和Mn吸气剂的SS 316L粉末进行了处理，并导致相似程度的氧气侵入。显微硬度测试表明，来自外部氧气的氧化物体积分数增加不会影响硬度值。但是，对于加湿和无Si-Mn的AM加工零件，发现硬度明显降低。