Microstructural and mechanical characterization of pre-mixed spray formed A357/SiCp composite

A spray formed aluminium alloy/SiCp composite, obtained by an alternative production route, was produced by mixing suitable amounts of A357.0 alloy and SiCp particles in the melting crucible of a laboratory scale gas atomiser, under a protective atmosphere. A mean volume fraction of reinforcing particles close to 15 vol.-% was achieved by properly choosing the melt superheat temperature and stirring speed. Microstructural characterisation of both the precomposite powders and of the spray deposited block was carried out by microscopy examination and X-ray diffraction. The variations of the volume fraction of reinforcement within the formed composite block were determined as a function of position and correlated to the corresponding local mechanical properties. The mechanical properties of the spray formed composite material are compared with those of the unreinforced alloy, spray formed in the same atomiser.