Research Article

Hot compression behaviour and microstructural evolution in aluminium based composites: an assessment of the role of reinforcements and deformation parameters

¹ Materials Design and Structural Integrity Research Group, Department of Metallurgical and Materials Engineering, Federal University of Technology Akure, P.M.B. 704, Ondo State, Nigeria
² Centre for Nanoengineering and Tribocorrosion, School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, South Africa
³ School of Chemical and Metallurgical Engineering, DST-NRF Centre of Excellence in Strong Materials and African Materials Science and Engineering Network (AMSEN): all University of the Witwatersrand, Private Bag 3, WITS, 2050, Johannesburg, South Africa
⁴ African Academy of Sciences, P.O. Box 24916-00502 Nairobi, Kenya

^* e-mail: babalolasaheed89@gmail.com

Received: 25 July 2020
Accepted: 31 January 2021

Abstract

The response of two different types of aluminium matrix composites (AMCs) reinforced with silicon carbide ceramic particulates or nickel metallic particulates to hot compression testing parameters was evaluated. The composites were produced via two-step stir-casting technique. Axisymmetric compression testing was performed on the samples at different deformation temperatures of 220 and 370 °Ϲ, 0.5 and 5 s⁻¹ strain rates and total strains of 0.6 and 1.2. The initial and post-deformed microstructures were studied using optical and scanning electron microscopy. The results show that flow stress was significantly influenced by imposed deformation parameters and the type of reinforcements used in the AMCs. Nickel particulate reinforced aluminium matrix composite (AMC) showed superior resistance to deformation in comparison with silicon carbide reinforced AMC under the different testing conditions. In both AMCs, work hardening, dynamic recovery and dynamic recrystallisation influenced their response to imposed parameters. The signature of dynamic recrystallisation was very apparent in aluminium matrix composite reinforced with nickel particulates.