Huber Florian, Bartels Dominic, Schmidt Michael
Institute of Photonic Technologies, Faculty of Engineering, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Straße 3/5, 91052 Erlangen, Germany.
Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander Universität Erlangen-Nürnberg, Paul-Gordan-Straße 6, 91052 Erlangen, Germany.
Materials (Basel). 2021 Jun 4;14(11):3095. doi: 10.3390/ma14113095.
High entropy or multi principal element alloys are a promising and relatively young concept for designing alloys. The idea of creating alloys without a single main alloying element opens up a wide space for possible new alloy compositions. High entropy alloys based on refractory metals such as W, Mo, Ta or Nb are of interest for future high temperature applications e.g., in the aerospace or chemical industry. However, producing refractory metal high entropy alloys by conventional metallurgical methods remains challenging. For this reason, the feasibility of laser-based additive manufacturing of the refractory metal high entropy alloy WMoTaNbV by laser powder bed fusion (PBF-LB/M) is investigated in the present work. In-situ alloy formation from mixtures of easily available elemental powders is employed to avoid an expensive atomization of pre-alloyed powder. It is shown that PBF-LB/M of WMoTaNbV is in general possible and that a complete fusion of the powder mixture without a significant number of undissolved particles is achievable by in-situ alloy formation during PBF-LB/M when selecting favorable process parameter combinations. The relative density of the samples with a dimension of 6 × 6 × 6 mm reaches, in dependence of the PBF-LB/M parameter set, 99.8%. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) measurements confirm the presence of a single bcc-phase. Scanning electron microscopy (SEM) images show a dendritic and/or cellular microstructure that can, to some extent, be controlled by the PBF-LB/M parameters.
高熵或多主元合金是一种很有前景且相对较新的合金设计概念。创造不含单一主要合金元素的合金这一想法为可能的新合金成分开辟了广阔空间。基于钨、钼、钽或铌等难熔金属的高熵合金对于未来的高温应用（例如在航空航天或化学工业中）具有吸引力。然而，通过传统冶金方法生产难熔金属高熵合金仍然具有挑战性。因此，在本工作中研究了通过激光粉末床熔融（PBF-LB/M）对难熔金属高熵合金WMoTaNbV进行激光增材制造的可行性。采用由易得的元素粉末混合物原位形成合金的方法，以避免预合金粉末昂贵的雾化过程。结果表明，WMoTaNbV的PBF-LB/M总体上是可行的，并且在PBF-LB/M过程中选择有利的工艺参数组合时，通过原位合金形成可实现粉末混合物的完全熔化且无大量未溶解颗粒。尺寸为6×6×6mm的样品的相对密度根据PBF-LB/M参数集达到99.8%。电子背散射衍射（EBSD）和透射电子显微镜（TEM）测量证实存在单一的体心立方相。扫描电子显微镜（SEM）图像显示出树枝状和/或胞状微观结构，在一定程度上可由PBF-LB/M参数控制。
