Research on the microstructure and electrical conductivity in hypereutectic Al-Si compacts and B4C added composites fabricated by conventional, microwave, and spark plasma sintering

In the present study, hypereutectic Al-Si alloy compacts and Al-Si/B4C composites were produced by conventional, microwave, and spark plasma sintering techniques. The effects of sintering techniques and B4C particle addition on microstructural properties, density, hardness, and electrical conductivity were investigated. The microstructures were examined with an optical microscope. Densities were measured using the Archimedes technique. Electrical resistance measurements were made using the four-point probe measurement technique. Elemental Al grains, master alloy grains, and primary Si particles were determined in the microstructures of all samples. The addition of 15 wt.% B4C caused the porosity rate to increase in the samples. Samples produced with the SPS technique gave approximate to 80 % higher hardness values than samples produced with CS and MWS. Compared to the samples produced with CS and MWS, the samples produced with SPS gave higher electrical conductivity values. Electrical conductivities were decreased as the weight percentage of B4C increased in all samples.