Bonding interfacial characterization of SiCp/8009Al composite and A356 aluminum alloy using compound casting

Compound casting was performed to investigate the bonding of the molten A356 aluminum alloy cast onto the SiCp/8009Al composite that was preheated at 395-450 °C. The bonding strength was measured by carrying out a tensile test. The interfacial microstructures were characterized by scanning electron microscopy, energy dispersive spectroscope, X-ray diffraction and electron backscattered diffraction. The results showed that the bonding strength increased by 37% when the preheating temperature increased from 395 °C to 420 °C, and decreased by 6.8% as the preheating temperature further increased to 450 °C. A transition zone where the Al4.5FeSi phases were distributed was formed. The grain size of the Al4.5FeSi phase increased while its density decreased from the SiCp/8009Al composite to A356 aluminum alloy. The transition zone widened from 1350 μm to 3200 μm as the preheating temperature increased from 395 °C to 450 °C. In addition, at the preheating temperature of 450 °C, the fracture position changed from the interface between the A356 aluminum alloy and transition zone (at the preheating temperature of 395 °C and 420 °C) to the interior of the transition zone. The interface formation mechanism and its effect on the fracture mechanism were also discussed.