Research On Interface Bonding Of Silicon Carbide Ceramic Foam/Aluminum Matrix Composites And Its Corrosion Behavior

In this paper, the SiC ceramic foam was prepared by organic foam impregnation and high temperature sintering method. Silicon carbide ceramic foam/aluminum matrix composites was fabricated by squeeze casting method, Si C ceramic foam and Al-Si alloy were selected as the reinforcement and the matrix material, respectively.By using optical microscope, scanning electron microscope(SEM), X-ray diffraction(XRD), energy disperse spectroscopy(EDS), brinell hardness tester, and electronic universal testing machine, the interface bonding of the composites was studied at the factor of different matrix material and pouring temperature. Its brinell hardness, bending strength and corrosion behavior were tested.The results are showed as follows:The bonding capacity of Al-Si alloy and Si C ceramic foam increases with the increasing of temperature. Under the condition of the temperature is below to 780℃,the interface is easy to separate. The appropriate pouring temperature is 780℃-810℃.The composites with well interface bonding can be fabricated as the hypoeutectic Al-Si alloy(ZL101), eutectic Al-Si alloy(ZL102) and hypereutectic Al-x Si(x=20-23)alloy are chosen for the matrix material. A transition zone with compact silicon phase is formed in the interface. The mechanism of the composites’ interface bonding is mixed, it exists mechanical interlock permeating layer and interfacial reaction.With the Si C ceramic foam’s aperture diameters increasing, the hardness and the flexure strength of composites are enhanced. And its high flexure strength is due to the good interface bonding. The fracture modes in Silicon carbide ceramic foam/aluminum matrix composites are mainly brittle fracture and cleavage fracture,but there are characteristics of ductile fracture in composites.The Al-xSi(x=20-23) exhibits superior corrosion resistance when compares with the composites. The SiC ceramic foam has large influence on the corrosion resistance of the composites. Increasing the volume fraction of the SiC ceramic foam could aggravate the corrosion process. SiC ceramic foam was not corroded. XRD shows that the components of the corrosion products of the composites are the same as thatof Al-x Si(x=20-23). The corrosion rates of both materials increase linearly as the temperature increasing. The influence of temperature on the corrosion rate depends on the dual factors of the activation energy and the variation of temperature in the corrosive medium. There are a large number of defects in the interface, which accelerate the corrosion of materials.