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Author(s): Michael N. Nwigbo, Umoru E. Lasisi, Youngson N. Ukaru.

Volume/Issue: Volume 5 , Issue 1 (2022)

Abstract:

This study synthesized a hybrid aluminium 6061 matrix composite with particulates of silicon carbide, SiCp and carbonized coconut shell (CCSP as reinforcements), and determined the effect of combining SiCp and CCSp reinforcements of different sizes and weight fractions on the strength properties and microstructure of the developed composite. The hybrid aluminium matrix composites were developed using the stir casting method. Several samples of the composites consisting of AA6061 alloy with 3, 6, 9, 12 and 15% by wt. each of CCSp and SiCp with average particle sizes of 38μm and 42.3nm for SiC, and 63μm and 50.01nm for CCSp were produced and characterized for strength. The microstructures of the developed composite materials revealed uniform distribution of reinforcement particles in the base matrix and excellent bonding between the base matrix and reinforcements after casting. The results obtained showed that addition of CCSp and SiCp reinforcement to the alloy increased the tensile strength and hardness. Also, a mathematical model was proposed for predictive tensile strength of nano-composite and validated by comparison with results of the physical experiment and those of other authors. The proposed model is in excellent agreement with experimental data. The nano-particulates reinforced composite presented maximum improvement in ultimate tensile strength value (53.4% and 8.5% of that for the unreinforced matrix and micro-composite respectively) at reinforcement level of 15wt.% nSiC/nCCS.

Keywords:

AA6061 alloy, stir casting, metal matrix composites, reinforcements, microstructure, nanoparticles.

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