Abstract
A powder metallurgy 2124 aluminium alloy–15 vol.-% SiC particle composite was annealed, and then underwent the standard T4 heat treatment. Changes of the matrix microstructures and mechanical properties of the composite owing to annealing were observed. The experimental results show that the distribution of dislocations close to the SiC particles tends to be uniform and the precipitate free zones around the SiC particles disappear, that the number of SiC particles on the fracture surfaces decreases and the shear area increases, and that the mechanical properties, particularly ductility and fracture toughness, of the composite are improved by the present heat treatment. Comparison of the mechanical properties, microstructures, and fracture morphologies of the T4 treated composite and that annealed and subsequently T4 treated indicates that a proper distribution of the matrix strength is beneficial to the alleviation of stress concentration and dislocation pile-up at the Al/SiC interface during the deformation process.
MST/1340
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