Effect of Aspect Ratio on the Workability of AA6082/Metakaolin/Nano Silicon Nitride Composites: An Experimental Investigation and Predictive Modeling using RSM and ANN

Articles in Press

Document Type : Research Article

Authors

1 Department of Production Engineering, PSG College of Technology, Coimbatore, 641004, Tamil Nadu, India

2 Department of Rural & Entrepreneurship Development, National Institute of Technical Teachers Training and Research, NITTTR, Chennai-600113, Tamil Nadu India.

3 Department of Mechanical Engineering, Dr. Mahalingam College of Engineering and Technology, Pollachi 642003, Tamil Nadu, India

4 Department of Mechanical Engineering, Gharda Institute of Technology, Khed, Ratnagiri, 415708, Maharashtra, India

Abstract

Understanding the impact of aspect ratio on the deformation and load-bearing capacity of aluminium matrix composites is crucial in tailoring their forming performance. In this study, aluminium alloy (AA) 6082/Metakaolin (MK)/nano silicon nitride (Si₃N₄) composites containing 7.5 wt.% MK and 1.5 wt.% Si₃N₄ were fabricated using ultrasonic cavitation-assisted stir casting and tested under quasi-static compression with cylindrical specimens of aspect ratios 0.5, 1, and 1.5 in both as-cast and T6 heat-treated conditions. The results showed that lower aspect ratios significantly enhanced workability. The as-cast composite at aspect ratio 0.5 sustained compressive deformation up to a 50% reduction in height without visible cracks, achieving a maximum axial stress of 573.25 MPa. The T6 heat-treated samples exhibited a maximum compressive strength of 543.31 MPa and fractured at lower strain due to embrittlement caused by eutectic Si and Mg₂Si phases. Microstructural analysis indicated pore closure as the governing deformation mechanism in as-cast specimens, while brittle fracture dominated the T6 samples. Instantaneous strain hardening exponent (nᵢ) and strength coefficient (kᵢ) trends confirmed contributions from both matrix and geometric work hardening during deformation. In order to predict the workability parameters for different aspect ratios and loadings, response surface methodology (RSM) and artificial neural network (ANN) were employed. ANN yielded superior prediction accuracy for the workability parameters compared to RSM. These findings confirm that aspect ratio strongly controls the deformation mechanisms, with shorter cylindrical specimens offering optimum workability for practical forming operations.

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Main Subjects

Mechanics of Advanced Composite Structures

Articles in Press, Accepted Manuscript
Available Online from 25 February 2026

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