Abstract
The tribological behavior of three bioinspired (BI) agro-waste ashes—bean pod ash (BPA), cassava peel ash (CPA), and coconut husk ash (CHA)—integrated as reinforcements in an alumina-reinforced AA6063 matrix hybrid and monolithic composite was investigated. Studies utilizing agro-wastes for bioinspired surfaces are limited despite these wastes posing significant environmental challenges. Consequently, there has been a growing effort to valorize these residues for sustainable engineering applications. This study uses a two-step stir-casting methodology to engineer bioinspired materials with lightweight properties, exceptional hardness, and wear-resistant characteristics. Microstructural investigations revealed a homogeneous distribution of natural and synthetic reinforcements within the AA6063 matrix. Lightweight AMCs were successfully fabricated, exhibiting densities ranging from 2.57 to 2.74 g/cm³ and hardness values between 81.28 and 107.47 BHN. The average surface roughness of these composites varied from 2.4 to 3.4 μm, with ANOVA tests confirming a statistically significant difference (p < 0.005). Wear rates and the coefficient of friction were observed to range from 2.52 x 10−3 to 5.50 x 10−3 mm³/m and 0.2476 to 0.5403, respectively. Reinforcing the AA6063 alloy with bioinspired agro-wastes significantly enhanced the hardness and tribological performance of the as-cast BI-AMCs. Notably, the wear rates and friction coefficients were significantly reduced, with the monolithic BI-AMCs demonstrating superior results. Furthermore, adding bioinspired agro-wastes, such as BPA, CPA, and CHA, improved the surface texture of AA6063 more effectively than Al2O3, leading to slightly smoother surfaces. These nuanced bioinspired tribological behaviors present opportunities for tailored load-bearing and aesthetic applications derived from agro-waste-based composites. This study advances our understanding of bioinspired tribological phenomena and paves the way for the development of innovative materials with diverse applications and enhanced performance.
•Novel agro-waste (BPA, CPA, CHA) particulates were reinforced with AA6063 alloy.•Microstructural analysis confirmed uniform ash distribution in the aluminum matrix.•The agro-wastes enhanced tribological and mechanical properties of the composites.•Environmental trade-offs of agro-waste were addressed with mitigation strategies.•Repurposing agro-waste into valuable materials via a circular approach was proposed.