Abstract
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 ≈ 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.

Key words
sintering, electrical conductivity, composite, Al alloy, microstructures

Full text (1526 KB)