OPTIMIZATION OF ALLOY-ALUMINA FIBER COMBINATION FOR MAGNESIUM BASED METAL-MATRIX COMPOSITES

Results are reported on the compositional and structural features of m etal/ceramic interfacial reactions in a series of magnesium based comp osites containing Al2O3 fibres (3 mu m diameter) produced via liquid m etal infiltration of preforms. The composites employed a range of matr ix compositions and fibres of different porosities and in some cases b inders were used. The practical objective was to optimise the combinat ion of matrix and fibre to reduce the extent to which alumina reacts w ith liquid magnesium. Detailed electron on microscopy has shown that t he dominant factor in minimising this reaction is reduction in the ext ent of interconnecting porosity in the fibres. The presence of alloyin g elements, such as aluminium in the matrix plays a more limited role in reducing the extent of interface reaction. (C) 1994 The Institute o f Materials.