Microstructure and Corrosion Characteristics of Dual Reinforced (SiC–B₄C) Al Matrix Composites Produced by Powder Metallurgy Process

In the current investigation, powder metallurgy was used for effective production of a hybrid aluminum matrix that was reinforced with SiC and B₄C particles. The effects of reinforcements (SiC and B₄C) on the microstructure of the composites, wettability and tribological behavior were examined. Aluminum (Al) matrix with reinforcements of silicon carbide (SiC) at weight percentages of 2, 3, 4, 5 and 6 was produced through powder metallurgy (PM) method, and also hybrid Al composites reinforced by SiC at different weight percentages of 2, 3, 4, 5 and 6 with constant addition of boron carbide (B₄C) with 2 wt.%. The microstructure analysis was carried out with a scanning electron microscope (SEM) indicated the uniform distribution of reinforcement particles throughout the aluminum matrix. The microstructures of aluminum showed an increase in porosity, with increase in SiC and B₄C concentration. Studies carried out using electron backscatter diffraction (EBSD) indicated the inclusion of SiC particles into Al composites bringing about a finer grain structure of the composite. The higher hardness value was obtained for Al + SiC(6 wt.%) and Al + SiC(4  wt.%) + B₄C(2  wt.%) composites as 50 and 54 HV, respectively. The composite’s hardness was enhanced as a result of grain refinement and increased resistance to dislocation motion. The higher compression strength was obtained for Al + SiC(4 wt.%) and Al + SiC(4 wt.%) + B₄C(2 wt.%) composites as 247 and 300 MPa, respectively. The Al + SiC(2 wt.%) and Al + SiC(6 wt.%) + B₄C(2 wt.%) composite samples’ thermal conductivity was 86.04 and 68.07 W/mK, respectively. The higher corrosion resistance of Al + SiC(2 wt.%) + B₄C(2 wt.%) hybrid composite sample was determined to be 0.706 mpy.