High strength Al2O3p/6061 Al composites: effect of particles,subgrains and precipitates

Abstract

Composites of 6061 Al reinforced by Al₂O₃ particles have been produced by squeeze casting followed by hot extrusion and a T4 precipitation hardening treatment. The tensile properties at room temperature have been determined and analysed based on microstructural parameters. The strength contributions from the matrix, particles, subgrains and precipitates have been estimated individually, and then based on an assumption of linear additivity, the yield stress values of the composites under the extruded and heat treated conditions have been calculated. Good agreement between the calculated and experimental values has been found, illustrating the suitability of the process for the manufacture of strong composites, with a maximum yield stress of 524 MPa obtained for a composite containing 60 vol.-%Al₂O₃.