In this study, Spark Plasma Sintering (SPS) was utilized to fabricate fine-grained cemented carbides, and an orthogonal experimental design was employed to examine the influence of holding temperature (1100 °C, 1200 °C, 1300 °C) and holding time (5, 10, and 15 min) on the performance of WC-10Co cemented carbide specimens. Compared with conventional sintering methods, this work achieved the production of samples with enhanced overall performance at lower temperatures and shorter durations. Specifically, under the conditions of a holding temperature of 1300 °C and a holding time of 5 min, the resulting specimens exhibited a density of 14.64 g/cm3, a hardness of 91.29 HRA, a fracture toughness of 16.39 MPa·m½, and a transverse rupture strength of 2398 MPa. The microstructural analysis revealed that as the holding temperature increased, the Co phase in the specimens underwent a transformation from its initial powder form to banded cobalt and subsequently to slit-shaped cobalt. It was found that the presence of banded cobalt effectively hinders crack propagation, whereas slit-shaped cobalt is more effective in preventing crack initiation, thus impacting the overall performance of the specimens. By analyzing the sintering curves and microstructures, the densification mechanisms during SPS sintering of WC-Co cemented carbides were elucidated. The study concluded that the state changes of the Co phase play a significant role in the densification behavior, final microstructure, and properties of the sintered material. These findings offer valuable insights for understanding and optimizing the SPS process.

中文翻译：

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放电等离子烧结制备WC-Co硬质合金的微观结构演变、力学性能和致密化机理


本研究采用火花等离子烧结 （SPS） 制备细晶粒硬质合金，并采用正交实验设计研究保温温度（1100 °C、1200 °C、1300 °C）和保温时间（5、10 和 15 分钟）对 WC-10Co 硬质合金试样性能的影响。与传统的烧结方法相比，这项工作实现了在较低温度和较短持续时间下具有增强整体性能的样品生产。具体而言，在保持温度为 1300 °C、保持时间为 5 min 的条件下，所得试件的密度为 14.64 g/cm3，硬度为 91.29 HRA，断裂韧性为 16.39 MPa·m1/2，横向断裂强度为 2398 MPa。微观结构分析表明，随着保温温度的升高，试样中的 Co 相经历了从最初的粉末形式转变为带状钴，然后转变为狭缝状钴。研究发现，带状钴的存在有效地阻碍了裂纹的扩展，而狭缝状的钴在防止裂纹萌生方面更有效，从而影响了试样的整体性能。通过分析烧结曲线和微观结构，阐明了 WC-Co 硬质合金 SPS 烧结过程中的致密化机制。该研究得出结论，Co 相的状态变化对烧结材料的致密化行为、最终微观结构和性能起着重要作用。这些发现为了解和优化 SPS 过程提供了有价值的见解。