Thermal Analysis of the Formation of Chunky Graphite during Solidification of Heavy-section Spheroidal Graphite Iron Parts

Analysis of cooling curves recorded at the centre of large blocks cast with near-eutectic spheroidal graphite cast irons prone to give chunky graphite has been checked against microstructure observations. It has been observed that solidification proceeds totally at temperatures lower than the stable eutectic temperature and the following solidification sequence could be proposed: 1) nucleation of primary graphite in the liquid; 2) initial eutectic reaction processing by growth of austenite-like dendrites encapsulating the primary nodules; 3) bulk eutectic reaction related to nucleation and then growth of CHG cells and of secondary nodules, these latter giving spheroidal graphite eutectic cells. It was found that the maximum recalescence during the eutectic reaction first increases with the volume of the block affected by chunky graphite, and then decreases when most of the material is affected. Interestingly enough, a relationship between the volume of the blocks affected by CHG and the recalescence measured on TA cups has been observed

Polymer–Ceramic Nanohybrid Materials

This review is dedicated to nanohybrid materials consisting of a polymer-based matrix and a disperse nanoscaled ceramic phase. Different preparation techniques for the synthesis of polymer–ceramic nanohybrid materials will be presented, such as blending techniques, sol–gel processing, in-situ polymerization, and self-assembly methods. Selected structural and functional properties of polymer–ceramic nanohybrid materials will be highlighted and discussed within the context of their dependence on parameters such as the homogeneity of the dispersion of the ceramic throughout the polymer matrix, the particle size of the ceramic phase, and the polymer–ceramic interface. Moreover, some advanced applications of polymer–ceramic nanohybrid materials will be addressed and compared with their polymeric counterparts