Phase-field modeling of wetting and balling dynamics in powder bed fusion process
Phase-field modeling of wetting and balling dynamics in powder bed fusion process
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DOI：
10.1063/5.0046771
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发表时间：
2021-01
影响因子：
4.6
通讯作者：
Lu Li;Ji-Qin Li;T. Fan
中科院分区：
文献类型：
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作者：
Lu Li;Ji-Qin Li;T. Fan
在粉末床熔融增材制造 (AM) 工艺中，成球效应对打印部件的表面质量有重大影响。表面润湿有助于粉末与基材之间的结合以及颗粒间的融合，而成球效应会在激光束周围形成大的球状珠，并在打印过程中导致空隙、不连续性和不良的表面粗糙度。为了更好地理解瞬态动力学，开发了一个具有简化二维配置的理论模型，以研究激光加热过程中的潜在流体流动和传热、相变和界面不稳定性。我们证明润湿程度和快速凝固抵消了成球效应，瑞利-高原流动不稳定性对于基材润湿性相对较低和扫描速率较高的情况起着重要作用。
In a powder bed fusion additive manufacturing (AM) process, the balling effect has a significant impact on the surface quality of the printing parts. Surface wetting helps the bonding between powder and substrate and the inter-particle fusion, whereas the balling effect forms large spheroidal beads around the laser beam and causes voids, discontinuities, and poor surface roughness during the printing process. To better understand the transient dynamics, a theoretical model with a simplified 2D configuration is developed to investigate the underlying fluid flow and heat transfer, phase transition, and interfacial instability along with the laser heating. We demonstrate that the degree of wetting and fast solidification counter-balance the balling effect, and the Rayleigh-Plateau flow instability plays an important role for cases with relatively low substrate wettability and high scanning rate.