WC-Co-Ce硬质合金的微观结构、力学和摩擦学性能：第一性原理计算和实验

Microstructure and Mechanical and Tribological Properties of WC-Co-Ce Cemented Carbide: First-Principles Calculations and Experiments

摘要:

建立了WC/Co和WC/CoCe界面模型，利用第一性原理计算了界面能、弹性常数和电荷分布特征。采用液相烧结法制备了 WC-10Co、WC-10Co-0.5Ce和WC-10Co-1Ce硬质合金。通过显微组织分析、力学性能测试和摩擦磨损测试，研究稀土元素Ce对硬质合金整体性能的影响。计算结果表明，Ce的掺杂促进了W和Ce原子在界面处形成强共价键，导致界面键能增加，界面能降低，结构稳定性提高。根据弹性常数和电子性能预测，合金的硬度、韧性和耐磨性都得到了提高。实验结果表明，当Ce含量为0.5wt%时， WC-10Co-0.5Ce硬质合金的性能最佳。在此浓度下，其维氏硬度达到1484 HV₃₀，断裂韧性为10.55 MPa?m^1/2，磨损率为 1.067×10^–5 mm³?N^–1?m^–1。

Abstract:

The WC/Co and WC/CoCe interface models were constructed, and the interfacial energy, elastic constants, and charge distribution characteristics were calculated using first-principles calculations. WC-10Co, WC-10Co-0.5Ce, and WC-10Co-1Ce cemented carbides were fabricated via liquid-phase sintering. Microstructural analysis, mechanical testing, and friction and wear testing were conducted to investigate the influence of the rare earth element Ce on the overall performance of the cemented carbide. The calculated results indicate that doping with Ce promotes the formation of strong covalent bonds between W and Ce atoms at the interface, which increases the interfacial bonding energy, reduces the interfacial energy, and improves structural stability. Based on the elastic constants and electronic properties, it is predicted that the hardness, toughness, and wear resistance of the cemented carbide are enhanced. Experimental findings demonstrate that the optimal performance is achieved when the Ce content is 0.5wt%. At this concentration, the Vickers hardness reaches 1484 HV₃₀, the fracture toughness is 10.55 MPa?m^1/2, and the wear rate is 1.067×10^–5 mm³?N^–1?m^–1.