Effect of copper content on the microstructures and properties of TiB2 based cermets by SHS

TiB2 based cermets with different copper content were produced from titanium powder, boron powder and copper powder by Self-propagating High-temperature Synthesis under conditions of Pseudo Hot Isostatic Pressing (SHS/PHIP). In order to obtain the optimal copper content, the effect of copper content on the microstructures and properties of TiB2 based cermets was investigated. The size of the TiB2 particles in the products decreased with increasing amounts of copper. The hardness (HRA) and bend strength increased firstly, then decreased with copper increasing. Their maximum values appeared at 20 wt.% and 40 wt.% copper, respectively. The porosity of TiB2 based cermets decreased with the copper content increasing due to good fluidity of copper. With the addition of copper, the fracture toughness of TiB2 based cermets increased gradually. Crack-tip plastic blunting by a ductile metallic phase and crack deflection are the principal mechanisms of toughness improvement of TiB2 based cermets. The range of optimal copper content in the TiB2 based cermets is between 40 wt.% and 50 wt.%.