Research on the Corrosion Behaviors of Austenitic Steel in Molten Aluminum Alloy

Abstract

Die corrosion has been a concern during aluminum alloy die casting. The casting parameters play a significant role in causing corrosion, such as the temperature of the aluminum alloy melt and working time. In order to study the effect of temperature and working time on dynamic corrosion behaviors, SDHA steel was stirred in molten ADC12 aluminum alloy at 650–800◦C. The corrosion morphology and corrosion product were investigated through X-ray diffraction (XRD) and scanning electron microscope (SEM) observations. The results show that the matrix reacts with aluminum alloy to form an Al8Fe2Si phase at experimental temperatures. The growth activation energy of the Al8Fe2Si phase is 89 kJ/mol. The dynamic corrosion rate rises with increasing temperature and holding time. The most serious corrosion was found when the experimental temperature reached 800◦C, which is closely related to the peeling of matrix and the formation of Al8Fe2Si at the grain boundary. Besides, the vanadium carbides in the matrix act as barriers to hinder the diffusion of Al and Si atoms effectively.