Consolidation, microstructure, and mechanical properties of a TiB2–Ni3Al composite

Since the use of metallic additives for the consolidation of tough TiB2-based materials results in a remarkable decrease of their hardness and oxidation resistance, the use of intermetallic compounds as binders for these materials has been thought to be an alternative choice. Taking into account the thermochemical behavior of TiB2 in contact with metallic elements and the desired mechanical properties for the resulting TiB2 composites, Ni3Al was selected as a suitable candidate. TiB2 + Ni + TiAl3 compacts were sintered by either pressureless sintering or hot isostatic pressing (HIP) at different temperatures up to 1600°C in order to obtain TiB2–Ni3Al specimens. Fully dense specimens were obtained after HIP and subsequently microstructurally and mechanically characterized. Comparison between TiB2–Ni3Al composites and some other selected TiB2-based ceramics and cermets shows that a better hardness/toughness compromise has been obtained for materials with the intermetallic binder.