Thermo-Fluid Modeling of Selective Laser Melting: Single-Track Formation Incorporating Metallic Powder
Thermo-Fluid Modeling of Selective Laser Melting: Single-Track Formation Incorporating Metallic Powder
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DOI：
10.1007/s11665-018-3574-5
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发表时间：
2019-02-01
影响因子：
2.3
通讯作者：
Chou, Kevin
中科院分区：
文献类型：
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作者：
Shrestha, Subin;Rauniyar, Santosh;Chou, Kevin
选择性激光熔化（SLM）利用激光源熔化和熔合金属颗粒以形成致密的固体部件。由于熔融金属具有表面张力梯度，因此热毛细效应成为熔体流动的驱动力，这将随后确定熔融/固化轨迹以及构建表面形态。在这项研究中，一个三维体积的流体模型已被开发，以模拟单轨道激光扫描过程中的传热和流体动力学。应用顺序粉末添加算法来获得厚基底上的随机粉末分布。Ti-6Al-4V的温度相关热物理性质用于定义材料，并包含体积热源作为激光照射的近似值。由于连续的熔化和凝固，热行为，熔融金属流动和自由表面的形成可以进行数值分析。此外，两层模拟已经进行了研究的层间结合。模拟结果与SLM实验进行了比较，使用单轨道形态获得的白光干涉。从模拟得到的熔池宽度与实测的单道宽度吻合得很好。另一方面，观察到SLM中形成的单个轨道具有升高的珠高度，这在数值上没有实现。
Selective laser melting (SLM) utilizes a laser source to melt and fuse metallic particles to form dense solid parts. Since molten metals have surface tension gradients, the thermo-capillary effect becomes a driving force of melt flow, which will subsequently determine the molten/solidified track as well as the build surface morphology. In this study, a 3D volume of fluid model has been developed to simulate heat transfer and fluid dynamic during single-track laser scanning. A sequential powder addition algorithm is applied to obtain random powder distribution over a thick substrate. Temperature-dependent thermo-physical properties of Ti-6Al-4V are used to define the material, and a volumetric heat source is included as an approximation to laser irradiation. As a result of continuous melting and solidifying, the thermal behavior, the molten metal flow and the free surface formation can be numerically analyzed. In addition, a two-layer simulation has been carried out to study the interlayer bonding. Simulations results are compared with SLM experiments using the single-track morphology acquired by white-light interferometry. The melt pool widths obtained from simulations are in good agreement with the measured single-track widths. On the other hand, it is observed that single tracks formed in SLM have an elevated bead height, which is not realized numerically.