|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Applications of Solidification Fundamentals
||An Electron Microscopy Study of Graphite Growth in Nodular Cast Irons
||Rawen Jday, Lydia Laffont, Jacques Lacaze
|On-Site Speaker (Planned)
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. Transmission electron microscopy has been used to characterize graphite nodules in as-cast state and in samples having been fully graphitized at various temperatures in the austenite field. Nodules in the as-cast material show a multi-fold structure characterized by an inner zone where graphite is misoriented and an outer zone where it is well crystallized. In heat-treated samples, graphite nodules consist of well crystallized sectors radiating from the nucleus. These observations suggest that the misoriented zone appears because of mechanical deformation when the liquid contracts during its solidification. During heat-treatment, this zone disappears by recrystallization. In turn, it can be concluded that nodular graphite growth mechanism is the same during solidification and solid-state transformation.
||Planned: Supplemental Proceedings volume