烧结温度对(Ti, W, Mo, Nb)(C, N)-(Co, Ni)金属陶瓷组织结构和性能的影响

本文以(Ti,W,Mo,Nb)(C,N)-(Co,Ni)基金属陶瓷材料为研究对象,研究烧结温度对金属陶瓷的成分、微观组织和力学性能的影响,初步探讨成分、微观组织与材料强度的关系。研究结果表明：烧结温度对(Ti,W,Mo,Nb)(C,N)-(Co,Ni)基金属陶瓷组织特征有显著的影响；合金的总碳(Ct%)随着烧结温度的提高而降低,当烧结温度达到1490℃时,合金总碳的急剧降低,导致合金组织中出现脱碳相(η相),从而使得合金的硬度(HV₃₀) 、断裂韧性(KIC)和抗弯强度(TRS)降低；1470℃烧结温度下,(Ti,W,Mo,Nb)(C,N)-(Co,Ni)基金属陶瓷合金的硬度(HV₃₀) 、断裂韧性(KIC)和抗弯强度(TRS)的匹配最佳,表现为在实际应用工况下的综合切削性能最优。

Effect of sintering temperature on the microstructure and machining performance of (Ti, W, Mo, Nb)(C, N)-(Co, Ni) cermets

In this study, dense Co- and Ni-bonded Ti(C_0.6N_0.4) matrix cermets with secondary carbides, i.e., WC, Mo₂C, and NbC, were prepared using liquid phase sintering in vacuum for 60 min at temperatures ranging from 1410 to 1490°C. The detailed microstructural and phase analysis was performed using scanning electron microscopy, electron probe microanalysis, and X-ray diffraction analysis. The effect of sintering temperature on the microstructure, mechanical properties, and machining performance of cermets was investigated. The results showed that sintering temperature had a significant impact on the microstructural characteristics of (Ti, W, Mo, Nb)(C, N)-(Co, Ni) cermets. The total carbon content of cermets decreased with increase in temperature and a carbon-deficient phase (M₆C) was observed in the cermet sintered at 1490°C. The cermets sintered at temperatures of up to 1470°C were composed of an fcc solid solution metal binder and two types of core-rim structured grains, i.e., cubic carbide solution and cubic Ti(C, N) solution phases. The best machining performance on continuous / interrupted turning was found in the cermet sintered at 1470°C because of an optimum combination of hardness and transverse rupture strength.