INTERFACES IN ALUMINA-FIBER-REINFORCED ALUMINUM PISTON ALLOYS

Fibre-matrix interfaces were investigated in alumina-short-fibre-reinf orced aluminium alloys. The composites were produced by squeeze castin g using pre-forms made of delta-alumina fibres (Saffil) or of alumosil icate fibres. Mostly the common piston alloy AlSi12CuMgNi was used as the matrix alloy, but some investigations were also performed on compo sites with a matrix of technically pure aluminium and the eutectic AlS i12 alloy. The piston alloy was used without any modification, with a strontium modification and with a lithium addition respectively. The c omposites were heat treated at 500-degrees-C for up to 60 days to stud y the thermal and chemical stabilities of the interface. The interface s were investigated mainly by analytical transmission electron microsc opy. The results are discussed with respect to wetting, adhesion and f ibre-matrix reactions.