Automated SEM/EDS Analysis for Assessment of Trace Cross-Contamination in 316L Stainless Steel Powders
Automated SEM/EDS Analysis for Assessment of Trace Cross-Contamination in 316L Stainless Steel Powders
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DOI：
10.1007/s11661-021-06474-4
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
M. Balart;Xinjiang Hao;C. Davis
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文献类型：
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作者：
M. Balart;Xinjiang Hao;C. Davis
在三个增材制造（AM）316L钢样品中的两个中观察到微裂纹后，进行了调查以确定根本原因。焊接图，考虑到成分和工艺参数，一般不能解释non-crackedversucracked AM 316L样品的实验观察。在所有三个AM样品的EBSD相图表现出完全奥氏体的显微组织，不仅在散装样品，但也近表面。AM样品中的微裂纹区域的分析表明，存在局部富集的Ni，Cu和P。对制备用于横截面检查的原料粉末样品的自动SEM/EDS分析显示，细的外来颗粒污染物，预计将在雾化过程中从NiCrCuP合金交叉污染中产生，完全嵌入316 L粉末颗粒中。这种类型的污染不会被发现的粉末安装在扫描电镜存根，一种常见的方法来评估粉末质量的检查。基于此分析，建议考虑在任何粉末质量控制标准化协议中包括粉末横截面的自动SEM/EDS分析，以增加检测和识别精细交叉污染物的机会。同时建议NiCrCuP合金的雾化不应再先于316L合金的雾化。
Following observations of microcracking in two, out of three, Additive manufactured (AM) 316L steel samples, an investigation was undertaken to ascertain the root cause. Welding diagrams, taking into account composition and process parameters, could not generally account for the experimental observations of non-crackedversuscracked AM 316L samples. EBSD phase maps in all three AM samples exhibited a fully austenitic microstructure not only in the bulk sample but also near-surface. Analysis of microcracked regions in the AM samples showed the presence of local enrichment of Ni, Cu and P. Automated SEM/EDS analysis on feedstock powder samples prepared for cross-section examination revealed a fine, foreign particulate contaminant, expected to arise from NiCrCuP alloy cross-contamination during atomization, to be completely embedded in a 316L powder particle. This type of contamination would not have been revealed on examination of powder mounted onto a SEM stub, a common approach to assess powder quality. Based on this analysis, it is recommended to consider including automated SEM/EDS analysis on powder cross-sections in any standardization protocol for quality control of powders, to increase the chances of detection and identification of fine cross-contaminants. It is also recommended that atomization of NiCrCuP alloy should no longer precede atomization of 316L alloy.