Some defects such as small pores, thermal damage of diamond particle and micro-cracks between diamond and metal matrix existed in SLM-fabricated metal-bonded diamond tools. For further application, it is vital to understand the formation mechanism of such defects by SLM-fabricated parameters. In this work, a multiphysics field numerical simulation model based on computational fluid dynamics (CFD) was developed to investigate molten pool evolution and defects formation mechanism for SLM-fabricated CuSn20-bonded diamond composites. From simulation results, the metal particles melt and flow forward under the action of the laser. Also, the presence of diamond particles can obstruct the normal flow of melted CuSn20 fluid. Increasing the laser power can widen and stabilize the molten pool, however, exacerbate the thermal damage of diamond particles. Specially, the migration and marginalisation of the diamond particles during the formation of molten pool were found by simulation and experimental results. Unavoidably, there are obvious gaps in the interfacial bonding region of diamond and CuSn20 due to the comprehensive reasons of thermal gradient, differences in thermophysical properties of two materials and undergo continuous migration and rotational behavior of diamond particles. These findings have potential value for understanding and optimizing the process of SLM-fabricated metal-bonded diamond tools.

中文翻译：

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选区激光熔化CuSn20/金刚石复合材料熔池演化及缺陷形成机制的数值模拟与实验研究


SLM制造的金属结合剂金刚石工具存在细孔、金刚石颗粒热损伤以及金刚石与金属基体之间存在微裂纹等缺陷。为了进一步应用，通过 SLM 制造参数了解此类缺陷的形成机制至关重要。在这项工作中，开发了一个基于计算流体动力学 (CFD) 的多物理场数值模拟模型，用于研究 SLM 制造的 CuSn20 金刚石复合材料的熔池演化和缺陷形成机制。从模拟结果来看，金属颗粒在激光的作用下熔化并向前流动。此外，金刚石颗粒的存在会阻碍熔化的 CuSn20 流体的正常流动。增加激光功率可以加宽和稳定熔池，但会加剧金刚石颗粒的热损伤。特别是，通过模拟和实验结果发现了熔池形成过程中金刚石颗粒的迁移和边缘化。由于热梯度、两种材料热物性差异的综合原因，金刚石与CuSn20的界面结合区域不可避免地存在明显的间隙，并且金刚石颗粒不断发生迁移和旋转行为。这些发现对于理解和优化 SLM 制造的金属结合剂金刚石工具的工艺具有潜在价值。