The Synthesis and Properties of Advanced Aluminium and Copper Based Metal Matrix Composites

This thesis studies the influence that submicrometric alumina particles (α-Al2O3) and milled carbon fibres (MCFs) have on the microstructure, hardness, mechanical properties, and wear of aluminium and copper matrices. The direct use of particulates (micrometric and nanometric scale) and carbon fibres (continuous and chopped) as reinforcement materials in Al-based and Cu-based alloys can potentially result in significant improvements in their property compared to existing Al-based and Cubased alloys. In this research, dual phase and hybrid (three-phase) composites were manufactured by introducing hard ceramic particles (α-Al2O3) and recycled MCFs (< 100 μm long) into Al and Cu matrices. An advanced powder metallurgy processing method was also developed to prepare precursor powder blends for consolidation by uniaxial hot pressing, after which their performance was investigated and compared. This research is divided into, (i) the preparation of precursor composite powders using the magnetically Uniball controlled milling technique, (ii) a synthesis of monolithic aluminium and copper composites using the uniaxial hot pressing technique, (iii) advanced characterisation X-ray diffractometry, field emission scanning electron microscopy (FSEM) equipped with energy dispersive spectroscopy (EDS), Archimedes density, electrical conductivity, resistivity, universal compression testing, Vickers micro-hardness, Ultra-micro indentation testing (UMIS), and wear testing. All the mechanical testing and wear testing of monolithic products was carried out at ambient temperature and atmosphere.