Can Raman Spectroscopy be Applied for Investigating Graphite Growth in Nodular Cast Irons

摘要

Growth of graphite during solidification and high temperature solid-state transformation has been investigated in samples cut out from a thin wall casting solidified partly in the stable (iron–graphite) and partly in the metastable (iron–cementite) systems. To this end, Raman spectroscopy has been used to characterize graphite nodules in as-cast state and in samples which have been fully graphitized at various temperatures in the austenite field. The results show no significant difference between Raman spectra recorded from these samples, suggesting that graphite grows with the same mechanism during either solidification or high-temperature (so-called first stage) graphitization. Transmission electron microscopy investigation is underway for complementing and checking these results.