Nanoindentation, Scratch, and Corrosion Studies of Aluminum Composites Reinforced with Submicron B4C Particles

The reported study examines the effect of submicron boron carbide particles on nanohardness, scratch resistance, and corrosion response of Al/B4C composites. Liquid metallurgy involving a combination of mechanical and ultrasonic stirring action is employed to produce composites with varying contents of B4C (0.5, 1, 1.5, and 2 wt%) particles. Fabricated composites are observed under field emission scanning electron microscopy (FESEM) and examined through energy dispersive X-ray (EDX) for particle incorporation and microstructural features. Nanoindentation hardness of alloy increased by 26.59% with just 2.0 wt% B4C and increased with increasing reinforcement. Scratch resistance increased, while wear volume decreased with higher reinforcement content. Scratch hardness is improved by 73% and 29% at 5 N and 20 N applied respective loads. Composites revealed an increase in friction coefficients with increasing applied scratch load. Potentiodynamic polarization and electrochemical impedance spectroscopy tests examined the corrosion properties of composites and base alloy. Surfaces corroded are characterized using the FESEM-EDX tool to understand the corrosion behavior. The incorporation of 0.5 wt% B4C significantly improved the corrosion resistance of Al-Si alloy. But further addition of submicron particles degraded the corrosion response.

Automated summary

The study demonstrates that increasing the content of B4C particles can enhance the hardness and scratch resistance of Al/B4C composites, while decreasing the corrosion resistance. Observations and tests conducted using FESEM and EDX provide insights into the microstructural changes and performance variations of the composites.