Thermal Shock Resistance and Ablation Behavior of TiB2-Cu-Ni Composite via Combustion Synthesis

Abstract

TiB2-Cu-Ni cermet composite was fabricated by self-propagating high-temperature synthesis combined with Pseudo Hot Isostatic Pressing. The microstructure of the composite is fine and uniform. The thermal shock resistance and ablation behavior of the TiB2-Cu-Ni composite was investigated by heating it for twenty seconds using a plasma torch arc heater. Fatal breakup took place in the monolithic TiB2 ceramic once the plasma arc flow faced the surface of the ceramic. Only a small crack was found on the ablation surface of the TiB2-Cu-Ni composite. The thermal stress fracture resistance parameter, R, and the critical energy release rate GIC of TiB2-Cu-Ni composite are at the same order with that of the W/Cu alloy. It showed that the properties of thermal shock resistance and the ablation of the composite are good. The fraction of mass loss of the homogeneous composite was 2.32 %, which was similar to that of traditional W/Cu alloy. The volatilization of the metal binder and mechanical erosion was the main mechanisms of the ablation.