Microstructural investigation and machining performance of NbC-Ti(C0.5N0.5) matrix cermets

Abstract

In this study, Ni or Co + Ni bonded NbC matrix cermets with secondary carbides (Mo2C and WC) as well as Ti(C0.5N0.5) were prepared by liquid phase sintering at 1450°C in vacuum. Detailed microstructural investigation was performed by SEM, EPMA and XRD analysis. The microstructure, mechanical properties as well as the C45 (HB140) steel turning performance of the cermets were investigated, and compared with a commercial Ti(C0.5N0.5) based cutting insert. The sintering results indicated that the partial substitution of NbC by Ti(C0.5N0.5) had a significant effect on the core-rim microstructure and refinement of NbC solution grains, as well as improved mechanical properties of the NbC-Ti(C0.5N0.5) cermets. The phase constitution and composition of the cermets were supported by thermodynamic equilibrium calculations. All sintered cermets were composed of a fcc solid solution metal binder and a cubic core-rim (Nb,Ti,Mo,W)(C,N) solution phase, as well as an independent Nrich Ti(C,N) phase. The NbC-Ti(C0.5N0.5) and Ti(C0.5N0.5) matrix cermets had a comparable HV30 of 1500-1600 kg/mm 2 and a similar fracture toughness of 8.0 MPa m 1/2 .

Microstructure and mechanical properties of WC and Ti(C0.7N0.3) modified NbC solid solution cermets

“…As summarised in Table 2, the average NbCss grain size, as determined by the line intercept method, is in the 1.30-1.60 μm range in the Ti(C0.7N0.3) containing cermets (12-32WC) and substantially increased to 3.65 μm in the Ti(C0.7N0.3) free cermet (52WC). A much smaller average NbC grain size is observed in the current WC and Ti(C0.7N0.3) modified NbC matrix cermets, as compared to NbC-Ni cermets [16].…”

“…Similar to Ti(C,N) based cermets, the NbC grain growth and morphology as well as mechanical properties of NbC based cermets can be adjusted by secondary carbides (WC, TiC, VC, Mo/Mo2C), carbonitrides (Ti(C0.5N0.5) or Ti(C0.7N0.3)) or a combination of these compounds [15,16]. However, the microstructural and mechanical properties evolution in NbC-Ti(C0.7N0.3)-WC-Mo2C-Co-Ni cermets has not yet been reported.…”

Microstructures and electrochemical behaviors of as‐cast magnesium alloys with enhanced compressive strengths and corrosion decomposition

“…Backscattered electrons possess strong penetrating ability, and also escape from the deeper position in sample, thus accurately characterizing elemental distribution on the alloy surface. [35][36][37][38] It is seen that Zr element is evenly dispersed on the surface. Mg element is less distributed in the secondary phase, which is consistent with the conclusion that the secondary phase is mainly composed of Mg-Zn compound.…”

Microstructure and mechanical properties of (Nb,W,Ti)(C,N)-Ni solid solution cermets with 6 to 20 wt% Ni

“…The mechanical properties of NbC-based cermets which depend on the ceramic and binder phases can be enhanced by varying the material compositions. VC, Mo/Mo2C, WC as well as a combination of the carbides with carbontride (TiC, Ti(C0.7N0.3) or Ti(C0.5N0.5)) were proven to be effective to limit NbC solution grains growth and result in an improved mechanical properties [12,13]. However, no data has been reported on the influence of Ni binder content on the microstructure and mechanical properties of NbC matrix cermets.…”