Gradient microstructure and multiple mechanical properties of AlSi9Cu alloy ribbon produced by melt spinning

The microstructure and mechanical properties of AlSi9Cu alloy ribbons produced by melt spinning were investigated by field emission gun scanning electron microscope (FEGSEM), X-ray diffraction (XRD), tensile and microhardness tests. The solidification time and cooling rate of the 54 μm thick ribbon were estimated to be 9 × 10−5 s and 5.72 × 106 K s−1 respectively. XRD results revealed supersaturated solid-solubility of Si in Al matrix to be 3.03 and 3.57 at.% for the wheel side and free surface of the ribbon separately. Microstructure evolution of three gradient regions along the cross-section of the ribbon was studied by SEM in detail, and fine spherical Si particles ranged from 12 to 290 nm were found to be distributed both in the Al matrix and the α-Al boundary. The ultimate tensile strength of the ribbon was as high as 383 MPa and 1.8 times higher than that of the conventional cast ingot, and the breaking elongation of the ribbon was about 1.5% with cleavage fracture feature, while the microhardness of the ribbon was 2.5 times higher than that of the ingot.