Spray atomized and deposited hypereutectic aluminum-silicon alloy

The presence of high silicon content in aluminum-silicon alloys results in the formation of coarse brittle silicon phase under conditions of slow solidification. In recent studies, an Al-17Si-4.5Cu-0.6Mg alloy was synthesized by the spray atomization and deposition technique in an attempt to modify the primary silicon phase. The master alloy was initially atomized using nitrogen gas and deposited on a cooling substrate. The microstructure of the spray deposited material was characterized using techniques of optical microscopy, scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The mechanical behavior of the spray deposited material was established through tensile and stress amplitude high-cycle fatigue tests. In this paper, the mechanical properties of the spray deposited material are compared with a conventional ingot metallurgy processed counterpart. The improved strength, ductility, cyclic fatigue and fracture resistance are discussed in light of intrinsic microstructural effects and deformation characteristics.