Investigating the Synergistic Impact of Cenosphere and Mg-Sn Alloy on the Tribological and Mechanical Properties of Aluminum Foam Composites

Abstract

The objective of this investigation is to enhance the mechanical and tribological properties of aluminum foam composites through the incorporation of cenospheres and a Mg-Sn alloy. Cenospheres, lightweight ceramic microspheres, are integrated as fillers within the metal matrix composites, capitalizing on their high strength-to-weight ratio and buoyancy. The synergistic effect of the Mg-Sn alloy addition is postulated to fortify the composite, augmenting its strength. These lightweight yet robust composites are poised to offer significant benefits in sectors demanding high performance and reduced weight, such as aerospace, automotive, and biomedical engineering. A meticulous examination of density, hardness, friction coefficients, and wear rates was conducted. It was observed that the inclusion of cenospheres precipitated a decrease in density from 2.51 to 2.01 g/cm 3 with a volume fraction increase from 0 to 55%. The introduction of 0.8% Mg-Sn alloy to a blend of 55% cenosphere and 44.2% aluminum resulted in a density increment to 2.14 g/cm 3 . Concurrently, the Vickers hardness exhibited an increase from 37 HV to 53 HV with a rising cenosphere concentration and further escalated to 57 HV upon the addition of the Mg-Sn alloy. Tribological testing revealed that the friction coefficient diminished from 0.293 to 0.235 µ with an escalated cenosphere volume from 25 to 55%. The integration of 0.4% Mg and 0.4% Sn alloy was demonstrated to significantly enhance the friction behavior compared to the pure aluminum and aluminum-cenosphere composites at a 55% volume fraction. The wear rate exhibited a pronounced decrease from 1.957 × 10 -6 to 1.1245 × 10 -6 g/cm under a 10 N load, which correlated with the increasing cenosphere content. This trend persisted under 20 N and 30 N loads, where wear rates diminished with a higher cenosphere volume fraction. The composition comprising 55% cenosphere and 0.8% Mg-Sn alloy manifested the lowest wear rates across varying stress conditions. Compression testing underscored a consistent decrease in compressive strength from 160 MPa to 65 MPa as the cenosphere content rose from 0 to 55%. However, the composite with 55% cenosphere sees a dramatic rise in compressive strength when Mg and Sn are introduced at 0.8 vol.%. Observed changes in density, hardness, friction and wear rates indicate that composite properties can be improved. These composites have the ability to combine mechanical strength with lightweight design, making them attractive for industrial applications.