Abstract The bilayer functionally graded WC-TiC-Co cemented carbides with different Co contents (6–14 wt%) have been successfully prepared by high pressure nitriding sintering in this study. The gradient microstructure from surface to interior was investigated to understand the microstructure evolution mechanism. The bilayer functionally graded cemented carbides are mainly characterized by outer layer and intermediate layer. The increase of Co content can promote more significant diffusion of Ti, C to form bilayer gradient microstructure and more noticeable Ti(C,N) and WC grain growth in outer layer and intermediate layer. The microhardness decreases from outer layer to intermediate layer and then increases again in the inner portion, while the fracture toughness profile shows the opposite trend.

中文翻译：

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Co含量对双层功能梯度硬质合金梯度微观结构演变和力学性能的影响

摘要 本研究通过高压渗氮烧结成功制备了具有不同 Co 含量（6-14 wt%）的双层功能梯度 WC-TiC-Co 硬质合金。研究了从表面到内部的梯度微观结构，以了解微观结构的演变机制。双层功能梯度硬质合金的主要特征是外层和中间层。Co含量的增加可以促进Ti、C更显着的扩散，形成双层梯度微观结构，外层和中间层的Ti(C,N)和WC晶粒生长更明显。显微硬度从外层到中间层降低，然后在内部再次增加，而断裂韧性剖面则呈现相反的趋势。