NiAl–Al2O3 composites produced by pulse plasma sintering with the participation of the SHS reaction

The paper presents the results of examinations of the NiAl–Al₂O₃ sinters (13, 38 and 55 vol% of Al₂O₃) produced from a mixture of nickel, aluminum and alumina powders in a single technological process, using the pulse plasma sintering (PPS) method. By subjecting the elemental powders to a PPS process for 900 s, we obtained NiAl–Al₂O₃ composites of a hardness ranging from 480 HV10 (13% Al₂O₃) to 680 HV10 (55% Al₂O₃). The fracture toughness of the sintered materials depended on the amount of the dispersed Al₂O₃ phase. When examined with a Vickers indenter under a load of 10 kg, the composite containing 13% of Al₂O₃ showed no cracking. In the composites with 38% Al₂O₃ and 55% Al₂O₃ contents, the value of K_IC was 9.1 and 8.2 MPam^1/2, respectively.