Effect of Al addition on the microstructures and compression properties of (TiCxNy–TiB2)/Ni composites fabricated by combustion synthesis and hot press

•The composites containing two-phase ceramics exhibit more superior properties.•Addition of Al can promote the reaction of Ni reacting with other elements.•Al additions strongly influence the microstructures and mechanical properties.•The combustion synthesis combined with hot press consolidation is in situ method.•The addition of Al could improve the interfacial bonding strength.

The 70 wt.% (TiCxNy–TiB2)/Ni composites were fabricated successfully by the combustion synthesis and hot press consolidation of the Ni–Ti–Al–B4C–BN powder mixtures. The addition of Al to Ni–Ti–B4C–BN system significantly decreased the ignition difficulty of combustion synthesis, and improved the compression properties of (TiCxNy–TiB2)/Ni composites. The final products mainly consist of Ni, TiCxNy and TiB2, and the ceramic particles distribute uniformly in the composites. With increasing Al content from 0 to 8 wt.%, the average sizes of the TiCxNy and TiB2 particles decrease a little, while the hardness and the compression strength increase firstly and then decrease, and the fracture strain increases. The composite with optimal 5 wt.% Al possesses the best comprehensive properties: the highest hardness (1794 Hv), the superior compression strength (3.76 GPa), and the fracture strain (4.2%), resulting in an overall increase by ~ 15%, ~ 28%, and ~ 45%, compared with these of the composite without the Al addition, respectively.

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