Abstract
Ti(C,N)-TiB2-Co cermets were in situ synthesized, via reactive hot pressing from the Co-Ti-C-BN system, with a Co content ranging from 6 to 22 wt%. The microstructure, relative density, hardness, and fracture toughness of the sintered compacts was investigated by light microscopy, scanning electron microscopy, ceramic densitometry, and Vickers hardness test. The investigations indicate that during hot pressing (compacting pressure = 30 MPa), when the Co content is 14–22 wt%, the metal binder is extruded. Co and Ti are included in the extrudate, breaking the original ratio and deteriorating the properties of the sintered products. As the Co content increases from 6 wt% to 12 wt%, the porosity increases, and the relative density increases from 97.2% to 99.5%. The fracture toughness increases from 6.1 to 6.8 MPa m1/2. The Vickers hardness first increases from 1897 HV10 to the maximum 1960 HV10 and then decreases slightly to 1945 HV10.
Highlights
Ti(C,N)-based cermets are widely used for finishing and semi-finishing cutting tools because of their excellent red hardness, low friction coefficient, and outstanding antiadhesion properties.[1,2] Many technologies such as hot pressing/sintering,[3] vacuum sintering,[4] hot isostatic pressing/sintering,[5] and reactive hot pressing (RHP) have been developed to fabricate Ti(C,N)-based cermets
The relative density increased from 97.2% to 99.5% (Figure 9(a)), and the fracture toughness increased from 6.1 to 6.8 MPamm1/2 with a Co content increasing from 6 to 12 wt% (Figure 9(b))
Ti(C,N)-TiB2-Co cermets with varying Co content from the Co-Ti-C-BN system were synthesized in situ via RHP
Summary
Ti(C,N)-based cermets are widely used for finishing and semi-finishing cutting tools because of their excellent red hardness, low friction coefficient, and outstanding antiadhesion properties.[1,2] Many technologies such as hot pressing/sintering,[3] vacuum sintering,[4] hot isostatic pressing/sintering,[5] and reactive hot pressing (RHP) have been developed to fabricate Ti(C,N)-based cermets. Advances in Mechanical Engineering the second-phase particles (such as TiB2, Al2O3, and Si3N4) were added to improve the hardness of Ti(C, N)-based cermets.[5,7,8] Studies by Yang et al.[9] and Xu et al.[6] show that the mechanical performance of Ti(C, N)-TiB2 cermets are better than that of monolithic TiB2 or Ti(C,N). Ti(C,N)-TiB2 cermets are prepared using a two-step method, that is, TiB2 and Ti are prepared first, and mixed-sintering is used with specific proportions.[4,10,11,12,13,14] mixing of the Ti(C,N) and TiB2 particles can introduce oxygen and other impurities
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