Tsaknopoulos Kyle, Walde Caitlin, Tsaknopoulos Derek, Cote Danielle L
Worcester Polytechnic Institute, Worcester, MA 01609, USA.
Solvus Global, LLC, Worcester, MA 01605, USA.
Materials (Basel). 2022 Aug 25;15(17):5853. doi: 10.3390/ma15175853.
Gas-atomized powders are frequently used in metal additive manufacturing (MAM) processes. During consolidation, certain properties and microstructural features of the feedstock can be retained. Such features include porosity, secondary phases, and oxides. Of particular importance to alloys such as Al 6061, secondary phases found in the feedstock powder can be directly related to those of the final consolidated form, especially for solid-state additive manufacturing. Al 6061 is a heat-treatable alloy that is commonly available in powder form. While heat treatments of 6061 have been widely studied in wrought form, little work has been performed to study the process in powders. This work investigates the evolution of the Fe-containing precipitates in gas-atomized Al 6061 powder through the use of scanning and transmission electron microscopy (SEM and TEM) and energy dispersive X-ray spectroscopy (EDS). The use of coupled EDS and thermodynamic modeling suggests that the as-atomized powders contain AlFe at the microstructure boundaries in addition to MgSi. After one hour of thermal treatment at 530 °C, it appears that the dissolution of MgSi and AlFe occurs concurrently with the formation of AlSiM, as suggested by thermodynamic models.
气雾化粉末常用于金属增材制造（MAM）工艺。在固结过程中，原料的某些性能和微观结构特征可以保留下来。这些特征包括孔隙率、第二相和氧化物。对于诸如Al 6061之类的合金而言，原料粉末中发现的第二相与最终固结形式的第二相直接相关，尤其是对于固态增材制造。Al 6061是一种可热处理合金，通常以粉末形式提供。虽然6061的热处理在锻造形式方面已得到广泛研究，但在粉末中研究该工艺的工作却很少。这项工作通过使用扫描和透射电子显微镜（SEM和TEM）以及能量色散X射线光谱（EDS）来研究气雾化Al 6061粉末中含铁析出物的演变。耦合EDS和热力学模型的使用表明，雾化态粉末除了含有MgSi外，在微观结构边界处还含有AlFe。根据热力学模型，在530°C下进行一小时热处理后，MgSi和AlFe的溶解似乎与AlSiM的形成同时发生。
