Abstract Powder bed fusion, the most popular technique in metal additive manufacturing, utilises two main energy sources: laser or electron beam. The laser powder bed fusion process is typically conducted under inert gas-filled environment, while electron beam melting (EBM) process is operated in vacuum. Regardless of energy source, powder flowability is a major concern as it affects the final product quality. The rotating drum, a tool to characterize flowability and assess powder behavior during recoating, is conducted in ambient air environment, which inaccurately mimics these processes. This work investigated Inconel 625 and Ti6Al4V in atmospheric (air/argon) and low-pressure environments. The gas type did not affect the powders' dynamic flow behavior, however, a systematic difference existed in low-pressure environment especially with smaller particle size. As current research explores finer powder cut in EBM processes, new ways to characterize powder flow in vacuum should be considered to optimise powder spreading in EBM environment.

中文翻译：

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研究在受控和低压环境中表征粉末流动的转鼓技术

摘要 粉末床融合是金属增材制造中最流行的技术，它利用两种主要能源：激光或电子束。激光粉末床熔融工艺通常在充满惰性气体的环境中进行，而电子束熔化 (EBM) 工艺则在真空中进行。无论使用何种能源，粉末流动性都是一个主要问题，因为它会影响最终产品的质量。转鼓是在重涂过程中表征流动性和评估粉末行为的工具，它是在环境空气环境中进行的，它不准确地模拟了这些过程。这项工作研究了大气（空气/氩气）和低压环境中的 Inconel 625 和 Ti6Al4V。气体类型不影响粉末的动态流动行为，然而，低压环境存在系统差异，尤其是粒径较小时。由于当前的研究探索了 EBM 工艺中更细的粉末切割，因此应考虑采用新方法来表征真空中的粉末流动，以优化 EBM 环境中的粉末扩散。