Cu-infiltrated (Nb,W)C solid solution carbides

Abstract

Binderless NbC with 0–25 wt% WC powder mixtures were pressureless sintered in vacuum at 1330, 1390 or 1450 °C to generate open porosity (Nb,W)C skeletons. The formation of residual minor amounts of W2C and WC was discussed as a function of WC addition and compared with thermodynamic predictions. The structures with 15–25 wt% WC addition with 16–35% open porosity were used as a skeleton for Cu infiltration at 1390 °C in H2. The microstructure of the as-sintered homogeneous (Nb,W)C grains in the skeleton changed into a core-rim structured grains after Cu infiltration due to the partial dissolution of Nb into the liquid Cu phase. The fracture toughness, hardness, Young's modulus, electrical conductivity and flexural strength of the as-sintered porous and near fully dense Cu-infiltrated materials were assessed and discussed.