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以N-甲基吡咯烷酮分散的石墨烯代替常规的冶金炭黑作为碳源,采用短流程原位还原碳化反应制备出纳米晶WC-Co复合粉末。采用放电等离子烧结系统对复合粉末进行快速烧结致密化。结果表明,石墨烯作为碳源可显著降低原位还原碳化反应温度,复合粉末粒径细小且分布均匀。得到的超细晶硬质合金块体材料平均晶粒尺寸约为290 nm,HV_(30)硬度值为13.877±0.131 GPa,断裂韧性KIC值为8.3±0.1 MPa·m~(1/2)。通过HRTEM观测表明,试样中WC/WC晶界、WC/Co相界、WC/C相界具有很高的匹配度。
N-methylpyrrolidone dispersed graphene instead of conventional metallurgical carbon black as a carbon source, using a short-flow in situ reduction carbonation reaction to prepare nanocrystalline WC-Co composite powder. Discharge plasma sintering system for rapid sintering of composite powder densification. The results show that graphene as a carbon source can significantly reduce the in situ reduction carbonation temperature, the composite powder size is small and uniform distribution. The average grain size of the obtained ultrafine grained cemented carbide block is about 290 nm, the HV 30 hardness is 13.877 ± 0.131 GPa, and the fracture toughness KIC is 8.3 ± 0.1 MPa · m 1/2. The HRTEM observations show that the WC / WC grain boundaries, the WC / Co phase boundaries and the WC / C phase boundaries in the sample have a high degree of matching.