Thermal properties of powder beds in energy absorption and heat transfer during additive manufacturing with electron beam
Thermal properties of powder beds in energy absorption and heat transfer during additive manufacturing with electron beam
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DOI：
10.1016/j.powtec.2020.11.082
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发表时间：
2020-12
影响因子：
5.2
通讯作者：
Yufan Zhao;Yuichiro Koizumi;K. Aoyagi;K. Yamanaka;A. Chiba
中科院分区：
文献类型：
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作者：
Yufan Zhao;Yuichiro Koizumi;K. Aoyagi;K. Yamanaka;A. Chiba
粉末床的性能直接影响到粉末床熔融（PBF）成形零件的质量。在激光PBF中，研究者们深入研究了粉末层对固结的影响。就与材料的相互作用机制而言，电子束不同于激光。因此，需要对电子束PBF进行深入的讨论。在这项研究中，数值模拟进行重建粉末床和分析随后的固结。粉末层的存在改变了发射率和热导率，使其不同于固体。对于具有不同粒度分布的粉末，热性能的差异导致熔池形成的改变。随着细粉含量的增加，发射率增加，导热系数降低。在给定的层厚下，随着细粉比例的增加，应该输入相对高的能量以确保优异的成形质量。
Powder bed properties affect the quality of the parts manufactured by powder bed fusion (PBF). On PBF with laser, researchers had thoroughly studied the impact of powder layer on consolidation. In terms of interaction mechanisms with materials, electron beam is different from laser. Thus, an in-depth discussion is required for PBF with electron beam. In this study, numerical simulations were performed to reconstruct the powder bed and analyze the subsequent consolidation. The powder layer's presence altered the emissivity and thermal conductivity to be different from those of a solid. Concerning the powder with different particle size distributions, the differences in thermal properties led to an alteration in the molten pool formation. The emissivity increased, and the thermal conductivity decreased as the fraction of fine powders increased. With the increased fraction of fine powders under a given layer thickness, relatively high energy should be input to ensure exceptional forming quality.