The effect of heat treatment on Fe-Ni/SiC composite

Abstract

The mechanical properties of Fe-Ni/SiC composite on five different soaking time were studied. The Fe-Ni/SiC composite consist of 78% Fe, 20% SiC and 2% Ni. The Fe-Ni/SiC composite was fabricated using powder metallurgy method; mixing, compaction and sintering. The powder mixtures were mixed for 2 hours. By using 250MPa pressure, the powder was pressed into a cylindrical shape with 18mm diameter. The green compacts were sintered at 900°C for 2 hours with the heating rate at 10°C. Quenching in water method was used for the heat treatment. The composite were then undergone 0, 2, 4, 6 and 8 hours of soaking time at 800°C for heat treatment. The composite system was characterized using optical microscope for microstructure, Principe Archimedes for density and porosity testing and Vickers Hardness testing. The composite microstructures were observed under optical microscope. The SiC particles as reinforcement were well distributed. The composites that undergone heat treatment has a higher density, 4.12g/cm3 compare with sinter composite, 2.97g/cm3. 6 hours soaking time has the lowest value of porosity, 3.61%. Hardness increases as the soaking period prolonged to 6 hours, from 52.63 HV to 78.33 HV. Over soaking to 8 hours will result in decrease of hardness to 59.23 HV. The optimum parameter to obtain the best properties is 6 hours soaking time, with highest hardness value and lowest porosity.