Microstructural investigation and mechanical properties of Al<sub>2</sub>O<sub>3</sub>-MWCNTs reinforced aluminium composite

Mohammad Na'aim Abd Rahim; Mohd Shukor Salleh; Saifudin Hafiz Yahaya; Sivarao Subramonian; Azrin Hani Abdul Rashid; Syarifah Nur Aqida Syed Ahmad; Salah Salman Al-Zubaidi; Mohammad Na'aim Abd Rahim; Mohd Shukor Salleh; Saifudin Hafiz Yahaya; Sivarao Subramonian; Azrin Hani Abdul Rashid; Syarifah Nur Aqida Syed Ahmad; Salah Salman Al-Zubaidi

doi:10.3934/matersci.2025017

AIMS Materials Science

2025, Volume 12, Issue 2: 318-335. doi: 10.3934/matersci.2025017

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Research article

Microstructural investigation and mechanical properties of Al₂O₃-MWCNTs reinforced aluminium composite

1.
Faculty of Industrial and Manufacturing Technology and Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
2.
Department of Mechanical Engineering Technology, Faculty of Engineering Technology, Universiti Tun Hussein Onn Malaysia, Hub Pendidikan Tinggi Pagoh, Km 1, Jalan Panchor, 84600 Pagoh, Muar, Johor Darul Takzim
3.
Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang Al-Sultan Abdullah, 26600 Pekan, Pahang Darul Makmur
4.
Department of Automated Manufacturing Engineering, Al-Khwarizmi College of Engineering, University of Baghdad, Baghdad, 10071, Iraq

Received: 11 February 2025 Revised: 16 April 2025 Accepted: 12 May 2025 Published: 21 May 2025

Hybrid reinforcement of metal matrix composites (MMCs), particularly those based on aluminum, is widely recognized for resulting in excellent mechanical properties, such as high strength-to-weight ratio, enhanced wear resistance, and superior thermal conductivity. In this study, multi-wall carbon nanotubes (MWCNTs) and alumina (Al₂O₃) were used as the reinforcement for aluminum A356 via electromagnetic stirring (EMS). The composite was fabricated by varying the Al₂O₃ and MWCNT contents. Molten MMCs were then poured into the mold, and samples were collected after solidification. The effect of hybrid reinforcement by EMS on the distribution of microstructure and mechanical properties was investigated. Optical microscopy (OM) revealed that the presence of Al₂O₃-MWCNTs as reinforcement refined the grains, evolving from dendritic to rosette. The grains became closely packed, and reduced porosity was observed. The intermetallic phases in the composite were identified using secondary electron imaging–field emission scanning electron microscope (SEI–FESEM) and X-ray diffraction (XRD). Mechanical properties of the matrix were measured using a universal testing machine and a Vickers hardness test. The results indicate that the reinforcement percentage and stirring time significantly impact mechanical properties. The best properties were obtained with 0.5 wt% MWCNT, 6 wt% Al₂O₃, and 10 min of stirring. Under these conditions, the highest values for yield strength (94 MPa), tensile strength (221 MPa), elongation at break (11.37%), and hardness (89 HV) were achieved. These findings show that an optimum amount of reinforcement content and stirring time greatly influence the mechanical properties of the composite. The results show that the EMS effectively overcomes common challenges associated with hybrid metal matrix composites, namely proper particle distribution, reduced porosity, and enhanced mechanical properties. EMS provides a practical solution for producing high-performance aluminum composites suitable for structural and thermal applications with lower costs.
- hybrid reinforcement,
- aluminum metal matrix composite,
- electromagnetic stirring
Citation: Mohammad Na'aim Abd Rahim, Mohd Shukor Salleh, Saifudin Hafiz Yahaya, Sivarao Subramonian, Azrin Hani Abdul Rashid, Syarifah Nur Aqida Syed Ahmad, Salah Salman Al-Zubaidi. Microstructural investigation and mechanical properties of Al2O3-MWCNTs reinforced aluminium composite[J]. AIMS Materials Science, 2025, 12(2): 318-335. doi: 10.3934/matersci.2025017

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Abstract

Hybrid reinforcement of metal matrix composites (MMCs), particularly those based on aluminum, is widely recognized for resulting in excellent mechanical properties, such as high strength-to-weight ratio, enhanced wear resistance, and superior thermal conductivity. In this study, multi-wall carbon nanotubes (MWCNTs) and alumina (Al₂O₃) were used as the reinforcement for aluminum A356 via electromagnetic stirring (EMS). The composite was fabricated by varying the Al₂O₃ and MWCNT contents. Molten MMCs were then poured into the mold, and samples were collected after solidification. The effect of hybrid reinforcement by EMS on the distribution of microstructure and mechanical properties was investigated. Optical microscopy (OM) revealed that the presence of Al₂O₃-MWCNTs as reinforcement refined the grains, evolving from dendritic to rosette. The grains became closely packed, and reduced porosity was observed. The intermetallic phases in the composite were identified using secondary electron imaging–field emission scanning electron microscope (SEI–FESEM) and X-ray diffraction (XRD). Mechanical properties of the matrix were measured using a universal testing machine and a Vickers hardness test. The results indicate that the reinforcement percentage and stirring time significantly impact mechanical properties. The best properties were obtained with 0.5 wt% MWCNT, 6 wt% Al₂O₃, and 10 min of stirring. Under these conditions, the highest values for yield strength (94 MPa), tensile strength (221 MPa), elongation at break (11.37%), and hardness (89 HV) were achieved. These findings show that an optimum amount of reinforcement content and stirring time greatly influence the mechanical properties of the composite. The results show that the EMS effectively overcomes common challenges associated with hybrid metal matrix composites, namely proper particle distribution, reduced porosity, and enhanced mechanical properties. EMS provides a practical solution for producing high-performance aluminum composites suitable for structural and thermal applications with lower costs.

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