Collected studies on interfaces and interphases as related to the behaviour of fibre-reinforced aluminium alloy composites

This paper is an essentially practical treatment of interphases and interfa ces and of their influence on the properties of a number of metal matrix co mposites (MMCs). The illustrations are drawn from the authors' experiences and have been chosen to underline the importance of detailed microstructura l analysis for elucidating the fabrication behaviour and the mechanical per formance of this group of materials. The work involves a series of MMCs bas ed upon different combinations of aluminium alloy and ceramic/carbon fibre (both continuous and short) and made using the method of low-pressure liqui d metal infiltration (LMI). Detailed analyses of the composite microstructu res are given. with particular attention being paid to the interface region s. The data are used to categorize an interface according to the type of bo nd, that is a mechanical bond resulting from thermal mismatch between the f ibre and metal matrix, or a chemical bond, with or without second phase, ca used by chemical reaction. The information is then employed to account for aspects of composite fabrication, such as the cast microstructure produced by the LMI method and the effect of heat treatment, and to elucidate compos ite properties such as stiffness, yield stress and failure strength.