Nanocrystalline NiAl-TiC Composites Sintered by the Pulse Plasma Method

The paper presents the results of the examination of nanocrystalline NiAl-TiC composites with 25 wt.% and 40 wt.% of TiC. The starting materials were coarse-grained powders which were subjected to mechanical refining to obtain a nano-crystalline grain size. These powders were then sintered using the pulse plasma method. After sintering the NiAl-TiC composites have a density of 99.9% of the theoretical value. The grain size, determined by X-ray diffraction using the Hall-Williamson method; density; hardness and fracture toughness of the composites were investigated. The results obtained showed that the pulse plasma sintered NiAl-TiC have a density very close to the theoretical value and that the nano-crystalline microstructure was maintained. The NiAl-TiC composites containing 25wt.% of TiC have a hardness of 750 HV1 and a stress intensity factor KIC of 7 MPa⋅m1/2, whereas those containing 40 wt.% of TiC have a hardness of 1070 HV1 and KIC of 11.8 MPa⋅m1/2.