Effect of copper content on the microstructures and properties of TiB ₂ 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.%.