The effect of aluminium content on morphology, size, volume fraction, and number of graphite nodules in ductile cast iron

摘要

The effect of aluminium content on the formation mechanism, volume fraction, morphology, and particle size distribution of graphite has been investigated. Addition of aluminium to ductile iron causes some fundamental changes in iron–carbon phase diagrams and, as a result, improves graphite formation during eutectic transformation. Results reveal that aluminium compounds have been formed in the core of graphite nodules; thus aluminium plays an important role in the formation of graphite nodules. Furthermore, it is indicated that an increase in the aluminium content also leads to an increase in the number of graphite nodules and a decrease in the nodule size. By using electron probe microanalysis, the segregation of aluminium and silicon between graphite nodules has been studied.