FABRICATION AND CHARACTERIZATION OF MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NANOCOMPOSITES BASED ON NICRALY ALLOY REINFORCED WITH SI3N4 PARTICLES BY SPARK PLASMA SINTERING METHOD

The present research has examined the effect of adding Si3N4 on the mechanical and structural properties of NiCrAlY alloy. The structural and mechanical properties of the manufactured samples were characterized by SEM, XRD,  micro-hardness evaluation and pin on disk wear test. Various concentrations of Si3N4 powder (1, 3, and 5 wt.%) were mixed with NiCrAlY powder using a mechanical ball mill. Next, the mixtures were sintered at 1100 °C using the spark plasma sintering (SPS) technique. The XRD patterns indicated that the samples were composed of two phases of solid solution γ-Ni(Cr) and intermetallic compounds β-NiAl. The results of micro-hardness measurements showed that adding 1% Si3N4 to NiCrAlY enhanced the hardness from 418 to 614 HV. However, with an increase in the Si3N4 content from 1 to 5 wt%, the hardness diminished from 614 to 543 HV, and by Adding Si3N4 to the NiCrAlY, its tribological properties were significantly improved.