Exploring the Mechanical and Structural Properties of B4C/ZrO2 Strengthened Al-Mg-Cr Alloy Hybrid Composites

Al-Mg-Cr alloys have been extensively used due to their inherent characteristics, including lightweight, high strength, resistance to corrosion, and recyclability. Still, the residues of various intermetallic phases cause grain boundary sliding and recrystallization at elevated temperatures, minimising their mechanical properties. This can be improved by adding suitable ceramic-strengthening particulates. The current study involved synthesizing B4C of varying weight proportions, retaining ZrO2 as a constant with Al-Mg-Cr alloy using a vacuum-assisted stir casting process; an ASTM standard investigated its microstructure and mechanical properties. Microstructure observation inferred that the ceramic strengthening particles are equally disseminated, and the Cu-Al2, Mg2Si, and Zn-Al2 eutectic precipitate at the grain boundaries of Al-Mg-Cr alloy solid solution. The mechanical properties of the 8wt% B4C+ 2wt% ZrO2 composite were improved compared to other combinations and the as-cast Al-Mg-Cr alloy. This improvement was attributed to enhanced wettability and grain refinement, resulting in increased hardness (26±0.06%), tensile strength (25±0.38%), compressive strength (20±0.31%), flexural strength (26.41±0.02%), and impact strength (23±0.03%). An ASTM B117 salt spray fog test was conducted to evaluate the corrosion resistance of the synthesized immixture. The test results indicated that the development of a protective layer of Al2O3 and AlB2 intrinsically enhances the corrosion resistance of the intermixture.