Influence of ausferrite microstructure decomposition on the corrosion properties of austempered ductile iron
Austempered ductile iron (ADI) belongs to the heat-treated class of ductile iron. The heat treatment consists of austenitization and the tempering process. The microstructure of an ADI sample is ausferrite consisting of acicular ferrite, carbon-saturated austenite and a graphite phase in the shape of nodules. The corrosion properties of ADI samples depend on the microstructure constituents and stability of the microstructure. In this paper, the influence of ausferrite microstructure decomposition on the corrosion properties of the ADI samples are presented. During the research, Tafel curve extrapolation and potentiodynamic polarization were used. It was found that the ausferrite microstructure decomposition very strongly affected the general corrosion behavior of the ADI samples.