Influence of T6 Heat Treatment on Densification, Mechanical, and Wear Behavior of Plantain Peel Ash Reinforced Aluminum Matrix Composites †

In this article, we investigate the impact of T6 heat treatment on Al/Mg/PPA composites’ microstructure, densification, wear, and mechanical properties. The samples were synthesized using a ball milling machine and spark plasma sintering (SPS). Microstructural analysis revealed homogeneously distributed Al, Mg, and PPA particles. However, microstructural defects such as micro-pores and cracks increased due to prolonged heating. Precipitations such as Al₂O₃, MgO, and MgAl₂O₄ were present in the composites, and no new phase was detected after the heat treatment. The grain size analysis showed that no significant grain growth occurred. The porosity of the composite samples increased significantly, with sample H4 (Al/2Mg/15PPA) displaying the highest porosity of 148.55% after the heat treatment. The composites’ hardness improved after the T6 heat treatment, with sample H2 (Al/2Mg/5PPA) displaying the maximum hardness of 69.4 HV, representing an increase of 12.48%. More significantly, the compressive strength of all the samples reinforced with PPA, dropped at a percentage range of 42.30–51.50% after the heat treatment. It can, therefore, be inferred from this investigation that the T6 heat treatment is most suitable for improving the hardness of heat-treatable aluminum alloys and composites rather than improving their overall properties.