Effect of Nano-B₄C Particulates on the Mechanical Properties and Corrosion Behavior of Magnesium (AZ91D) Matrix-Based Nanocomposites Fabricated through Ultrasonication-Assisted Stir Casting Method

In recent times, there has been a marked rise in the demand for high-performance, lightweight composite materials for various engineering applications, notably in the automobile and aerospace industries. This study focuses on the fabrication of AZ91D-B₄C nanocomposites containing different proportions of B₄C nanoparticles (0.5, 1, 1.5 and 2 wt.%) using a method that combines ultrasonication with stir casting. The study explored how the inclusion of nano-B₄C particles influences the mechanical characteristics and resistance to corrosion of the nanocomposites. Characterization tools such as X-ray diffraction (XRD), Optical microscopy (OM), and Field emission scanning electron microscopy equipped with energy-dispersive spectroscopy were utilized to assess the phase composition, surface features, and microstructure of both the nanocomposites and the base alloy. The findings revealed a relatively even distribution of B₄C nanoparticles throughout the matrix and strong bonds at the interface between the B₄C particles and AZ91D matrix. Consequently, the mechanical properties, including microhardness, yield strength and tensile strength, were significantly improved by incorporating B₄C nanoparticles. Moreover, the corrosion testing indicated that the nanocomposite with 1.5 wt.% B₄C displayed the highest corrosion resistance when compared to other variants, as evidenced by both in polarization analysis and immersion test.