In-situ Synchrotron imaging of keyhole mode multi-layer laser powder bed fusion additive manufacturing
In-situ Synchrotron imaging of keyhole mode multi-layer laser powder bed fusion additive manufacturing
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DOI：
10.1016/j.apmt.2020.100650
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发表时间：
2020-09-01
影响因子：
8.3
通讯作者：
Lee, Peter D.
中科院分区：
文献类型：
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作者：
Chen, Yunhui;Clark, Samuel J.;Lee, Peter D.
激光粉末床熔融（LPBF）增材制造中的锁孔模式可能与过度孔隙和飞溅有关，然而，多层构建条件下的潜在物理特性尚不清楚。在这里，我们使用超高速同步加速器x射线成像来揭示这一现象。我们研究了熔池动力学、锁孔孔隙率和飞溅形成机制及其对所有层的影响。我们观察到，与锁孔相关的瞬态熔池动力学包括：(I)锁孔启动，（II）锁孔发展和（III）熔池恢复。孔隙度和飞溅与（II）和（III）阶段有关。我们还发现，在（III）阶段，由于锁孔反冲区坍塌，会形成液滴飞溅，导致熔融颗粒聚集和喷射。我们的研究结果阐明了多层LBPF工艺中锁眼模式背后的瞬态动力学，可以用于指导增材制造中减少孔隙率和飞溅。(c) 2020 Elsevier Ltd.版权所有。
The keyhole mode in laser powder bed fusion (LPBF) additive manufacturing can be associated with excessive porosity and spatter, however, the underlying physics in multilayer build conditions remain unclear. Here, we used ultra-fast synchrotron X-ray imaging to reveal this phenomena. We in investigated melt pool dynamics, keyhole porosity and spatter formation mechanisms and their impact in all layers of the build. We observed that the transient melt pool dynamics associated with the keyhole include: (I) keyhole initiation, (II) keyhole development, and (III) melt pool recovery. Porosity and spatter were associated with stages (II) and (III). We also discovered that droplet spatter can form due to the collapse of the keyhole recoil zone, causing molten particle agglomeration and ejection during stage (III). Our results clarify the transient dynamics behind the keyhole mode in a multi-layer LBPF process and can be used to guide the reduction in porosity and spatter in additive manufacturing. (c) 2020 Elsevier Ltd. All rights reserved.