Selective laser melting (SLM) is an effective and potential technology to prepare metal-matrix diamond composites (MDC). In this study, balling phenomenon and graphitization of diamond of CuSn10-diamond composites by SLM were investigated. By univariate analysis of laser power and scanning speed on the morphology of single track, the balling phenomenon is directly affected by the flowability and wettability of the molten pool. By introducing the concept of laser energy density, balling and diamond graphitization are quantitatively evaluated by the standard deviation σ of surface balling height and I: I value, respectively. Balling degree increases with laser energy density, but diamond-graphitization turns out to be the opposite. The CuSn10-diamond composites with low balling and no diamond-graphitization can be obtained at moderate laser energy density of 0.17 J/mm. In terms of performances, bending strength is mainly affected the defects caused by balling, and wear properties is determined by the graphitization of diamond abrasives. Graphitization of diamond results in the transformation of wear mechanism from abrasive to adhesive wear. The optimal properties of 185.36 MPa in bending strength, 0.41 in coefficient of friction and minimum wear loss is obtained in the composite sample prepared at 0.17 J/mm.

中文翻译：

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选择性激光熔化金属基金刚石复合材料的成球行为和金刚石石墨化：定量研究


选择性激光熔化（SLM）是制备金属基金刚石复合材料（MDC）的一种有效且有潜力的技术。本研究通过SLM研究了CuSn10-金刚石复合材料的成球现象和金刚石的石墨化。通过激光功率和扫描速度对单道形貌的单变量分析发现，成球现象直接受到熔池流动性和润湿性的影响。通过引入激光能量密度的概念，分别通过表面球化高度的标准差σ和I：I值来定量评价球化和金刚石石墨化。球化程度随着激光能量密度的增加而增加，但金刚石石墨化却相反。在0.17 J/mm的中等激光能量密度下，可以获得低球化且无金刚石石墨化的CuSn10-金刚石复合材料。从性能上看，弯曲强度主要受球化缺陷影响，磨损性能则由金刚石磨料的石墨化程度决定。金刚石的石墨化导致磨损机制从磨料磨损转变为粘着磨损。在0.17 J/mm下制备的复合材料样品获得了最佳性能，弯曲强度为185.36 MPa，摩擦系数为0.41，磨损量最小。