Mechanical properties of aluminium matrix composites reinforced with intermetalics

Abstract

In this work 2124 aluminium matrix composites reinforced with Ni₃Al, NiAl, MoSiO₂ and Cr₃Si intermetallic powder particles have been investigated. For comparision purposes, unreinforced 2124 and reinforced with SiC have also been studied. In all cases, the same powder metallurgy route was used, i.e. the 2124 alloy was obtained by rapid solidification and the intermetallic particles by self-propagating high-temperature synthesis (SHS). The matrix and the intermetallics were mechanically blended, cold compacted and finally hot extruded. Tensile tests were carried out in T1 and T4 treatments. Results indicate that mechanical properties depend strongly on the tendence to form new phases at the matrixintermetallic interface during procesing and/or futher thermal treatments. The materials which present better properties are those that present less reaction between matrix and intermetallic reinforcement, i.e. MoSiO₂ and SiC reinforced composites.