Effect of NbC on Microstructure and Mechanical Properties of WC-Based Cemented Carbides AITranslate

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Chinese Library Classification Number:TG135.5[一般工业技术]

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To improve the comprehensive properties of WC-based cemented carbides,WC-based cemented carbides with different mass fractions(0,0.6%,0.8%,1.0%,1.2%and 1.4%)of NbC added were prepared via pressureless melt infiltration using Cu-10Ni-5Mn-3Sn as the binder alloy.The effects of different NbC contents on the microstructure and mechanical properties of cemented carbides were analyzed by scanning electron microscope,energy dispersive spectrometer,X-ray diffractometer,universal testing machine,and Rockwell hardness tester.The action mechanism of NbC as an inhibitor was also explored.The experimental results show that the dissolution-precipitation process of WC in the binder phase is slowed down by adding an appropriate content of NbC(≤1.0%),resulting in grain refinement.When NbC is added in excess(>1.0%),the brittle Ni₂W₄C,Nb₄Ni₂C,and(Nb,W)C gradually form.As the NbC content increases,the average grain size of WC in the alloy first decreases and then increases,the hardness and bending strength first increase and then decrease,and the fracture toughness first decreases and then increases.After adding 1.0%NbC,the hardness and bending strength of the alloy reach their maximum values of 93.4 HRA and 1808.8 MPa,respectively.At this time,the fracture morphology of the alloy is mainly brittle fracture,and the fracture toughness value is relatively low.