TEM Investigation of Interfaces Formed between SaffilTM Fibers and AA6061 and En Ac 44200 Aluminium Alloys

Abstract

The metal matrix composites (MMC) were produced by force infiltration of preforms containing up to 10 vol % of Saffil fibers with AA6061 and EN AC 44200 aluminium alloys. The fibers were stabilized inside preform by dipping in liquid glass and heat treated at 800oC/2 hours. It allowed both to coat fibers with a thin layer of silica and bond fibers with amorphous silica bridges producing self supporting porous structure. The microstructure observations were performed using Tecnai FEG (200kV) transmission electron microscope. The performed investigations showed that infiltrating preform with AA6061 alloy with ~1 wt. % Mg caused reaction of silica with liquid metal substituting the former with porous amorphous Al2O3. A presence of MgO at the interfaces with aluminium matrix was noted. The infiltration with low magnesium EN AC 44200 (Mg <0.6 wt.%) alloy helped to produce composite with the silica bridges between fibers practically intact.