Effect of nano addition on the microstructures and mechanical properties of Ti(C, N)-based cermets

The influence of nano TiC and TiN additions on the mechanical properties of Ti(C, N)-based cermets was studied. A cermet with proper amount of TiC and TiN additions, which had more than twice the transverse rupture strength (TRS) of a typical cermet, was manufactured. The microstructures of the prepared cermets with nano additions were studied further by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX). It was found that in the cermets with nano additions, the amount of smaller grains without obvious rim phase and those with “white core-black rim” increased greatly. In addition, the volume fraction of binder phases reduced apparently. Some smaller ceramic particles were also found to be inlaid in the rim of the larger ceramic grains and kept partial coherent with the larger grains. It was the firm joint between them and the reduction of the average size of the grains that led to strengthening and toughening of the cermet with nano additions.