Exploring the Mechanical Strength and Microstructure of Aluminium-Coconut Shell Ash Composites

Abstract

This study investigates the mechanical performance and micro-structural characteristics of a sustainable aluminium matrix composite reinforced with coconut shell ash (CSA), an underutilized agro-waste material. The novelty of this work lies in the systematic integration of CSA as a low-cost, eco-friendly reinforcement and the establishment of clear structure-property relationships across a wide composition range (2-12 wt.%). Coconut shell ash was produced via controlled thermal treatment, characterized using atomic absorption spectroscopy, and incorporated into molten aluminium through stir casting to ensure uniform dispersion. The results demonstrate a significant enhancement in mechanical properties with increasing CSA content, with tensile strength peaking at 65.8 N/mm² and hardness reaching 88.20 HR. Micro-structural analysis confirms homogeneous particle distribution and improved inter-facial bonding, which are responsible for the observed strengthening mechanisms. Unlike conventional ceramic reinforcements, CSA offers a lightweight and sustainable alternative while maintaining competitive performance.This work advances current knowledge by linking agro-waste-derived reinforcement characteristics to mechanical behavior in aluminium composites and demonstrates the viability of CSA as a functional engineering material. The findings provide a pathway for developing cost-effective, high-performance composites for structural applications in automotive, aerospace, and construction industries, while promoting circular economy and environmental sustainability.