网状结构硬质合金界面钴相扩散过程研究

Research on Interfacial Diffusion Process of Cobalt Phase in Cellular Cemented Carbide

网状结构硬质合金是一种具有新型微观组织结构的硬质合金复合材料,而界面钴相梯度控制是网状结构硬质合金研究的关键技术。本文以YG20C作为网状合金的基体、YG6X作为团粒制备网状硬质合金试样,结合SEM、EDS等检测手段,研究烧结温度与保温时间对界面钴相扩散的影响。并通过相图计算、第一性原理等理论计算方法对钴相扩散的过程进行进一步研究证明。结果表明,当烧结温度高于1 340℃时,即使很短的保温时间界面钴相也很容易扩散均匀,当温度低于1 320℃,即使延长保温时间,核壳组织两边的钴相含量没有明显的变化,即界面钴相扩散受到了抑制。实验结果与理论计算相符合。

Cellular cemented carbide is a kind of composite material with novel microstructure. The control of the gradient of cobalt phase on the interface is a key technology for the research of cellular cemented carbide. Cellular cemented carbide samples were prepared by using matrix of YG20C and agglomerates of YG6X, combined with the testing methods including SEM and EDS, the effects of sintering temperature and holding time on the interfacial diffusion of cobalt phase were investigated. Through the calculation of phase diagram and the First-principle calculation method, the diffusion process of cobalt phase was further studied. The results indicate that the interfacial diffusion of cobalt phase is fast and uniform in a short time above 1 340℃. While the diffusion is restrained even after a long holding time below 1 320℃, the content of cobalt phase is not obviously influenced in both sides of the core-shell structure, i.e. the diffusion of cobalt phase is inhibited. The experimental result is in agreement with the theoretical calculation.