Influence of carbon content on the sinterability of an FeCr matrix cermet reinforced with TiCN

The influence of carbon content on an iron–chromium cermet composite reinforced with Ti(C,N) (50 vol.%) has been studied. A thermodynamic simulation was performed using the ThermoCalc software to calculate the phase diagram of the composite. The results were validated by a thermal study performed using differential thermal analysis (DTA), and cermet samples with C percentages between 0 and 1 wt.% added to the steel matrix were prepared using a conventional powder metallurgy process. The sintered samples were characterised by measurements of density and hardness, microstructural analysis using scanning electron microscopy (SEM), microanalyses using energy dispersive X ray spectroscopy (EDX) and X-ray diffraction (XRD). The results obtained show a significant influence of the C percentage on the solidus temperature, which influences sintering behaviour, leading to changes in the Ti(C,N) particles' shape and composition, due to changes in the stoichiometry of the Ti(C,N). This influence is reflected in the cermet microstructure and hardness. The results are discussed with reference to the DTA and thermodynamic studies.

► Complete investigation of a stainless steel matrix cermet.
► Strong influence of C content on the thermal response, reducing solidus and liquidus.
► Homogenous microstructure with cubic Ti(C,N) particles and ferrite matrix.
► Sintering mechanism explained with the aid of thermodynamic simulation diagrams.
► Relationship among C content, hardness and lattice parameter of the TiCN.