Particle shape is one of the most important powder attributes affecting the properties of multiphase compounds intended for metal injection molding. This work reports the processability of gas (GA) and water (WA) atomized Co-Cr-Mo-Si alloy related to quantitative analyses of particle shape using a newly developed algorithm based on the Euclidean distance mapping, which results are compared with those of commercially available dynamic image analysis. Both methods reveal similar values for the parameters that quantify the shape of the powders, such as circularity, aspect ratio, and symmetry. The alloys were mixed with wax/high-density polyethylene (50/50 wt%) binder using a double sigma mixer to produce homogeneous feedstocks. The critical solid loading and flow performance corresponding to the differences in powder shapes were derived from the torque and capillary rheometers, respectively, to obtain the optimum molding parameters. A stable and repeatable viscosity was observed for the GA feedstock, whereas the compound containing WA was prone to phase separation during flow. The defect-free sintered specimens were examined by metallographic analysis; the GA powder compound could be sintered to a maximum of 99.2 % of the theoretical density, whereas the irregular WA powder reached a maximum of 98.8 % of the theoretical density, and the carbon residue was found to be higher for the GA feedstock. The GA samples had a significantly higher ultimate tensile strength owing to their larger symmetry, which resulted in a lower porosity and stress concentration.

中文翻译：

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Co-Cr-Mo-Si 多相化合物形状参数的量化及其在金属注射成型原料加工中的作用

颗粒形状是影响金属注射成型多相化合物性能的最重要粉末属性之一。这项工作报告了气雾化 (GA) 和水雾化 Co-Cr-Mo-Si 合金的加工性能，该合金与颗粒形状的定量分析相关，使用基于欧几里得距离映射的新开发算法，并将结果与商业上可用的动态图像分析。两种方法都揭示了量化粉末形状的参数的相似值，例如圆形度、长宽比和对称性。使用双西格玛混合器将合金与蜡/高密度聚乙烯（50/50 wt%）粘合剂混合以生产均质原料。分别通过扭矩和毛细管流变仪得出与粉末形状差异相对应的临界固体负载和流动性能，以获得最佳成型参数。 GA 原料具有稳定且可重复的粘度，而含有 WA 的化合物在流动过程中易于发生相分离。对无缺陷的烧结试样进行金相分析； GA粉末化合物可以烧结到理论密度的最大99.2%，而不规则的WA粉末达到理论密度的最大98.8%，并且发现GA原料的残炭更高。 GA 样品由于其较大的对称性而具有显着较高的极限拉伸强度，从而导致较低的孔隙率和应力集中。