Corrosion Characteristics of AZ31-B₄C Composites

In this research, influence of boron carbide (B4C) particles on the corrosion behavior of magnesium metal matrix composite is examined. AZ31-B4C composites are fabricated through ultrasonic vibration-assisted stir casting process by reinforcing varying amount of boron carbide (0.5-2 wt.%) in AZ31 alloy. Characterizations of the composites are carried out using optical microscope , scanning electron microscope (SEM) and energy-dispersive spectroscope (EDS). The optical images show equiaxed orientation of grains in fabricated composites. SEM analysis confirms uniform distribution of reinforcement particles in composites. EDAX result confirms the inclusion of B4C particles in the Mg matrix. The microhardness of all composites and base alloy is measured using Vickers's microhardness tester. Microhardness values are found to be increased with increase in wt.% of B4C nanoparticles. Electrochemical corrosion tests are carried out on AZ31-B4C metal matrix composites in 3.5% NaCl solution. AZ31-1B(4)C composite is found to be the most corrosion-resistant material among tested materials. Furthermore, corrosion morphology of samples is scrutinized under SEM and EDS.