Interface study of short mullite fibre reinforced Al–Cu–Mg alloy composites

Abstract

Short mullite fibre reinforced Al–Cu–Mg alloy composites were produced by squeeze casting. The interfacial microstructure and microchemistry of the testing composites were studied by means of X-ray diffraction (XRD), transmission electron microscope (TEM) and energy disperse spectroscope (EDS) equipped with TEM respectively. It is shown that chopped mullite fibres in the composites are polycrystalline in structure composed of many fine mullite crystal particles which are orthorhombic in structure with lattice constants of a=0·749, b=0·927 and c=0·581 nm based on electron diffraction (ED) analysis and high resolution transmission electron microscope (HRTEM). There are highly densified dislocations in the vicinity of mullite fibre/matrix interface after solution treatment and quenching in ice water immediately. Interfacial reaction between mullite fibre and Al–Cu–Mg base alloy was observed, resulting in the formation of MgAl 2 O 4 spinels in the testing composites.