In-situ X-ray radiography of primary Fe-rich intermetallic compound formation
Professor Patrick Grant, Dr Shikang Feng, Dr Enzo Liotti, Dr Andrew Lui and researchers from Rutherford Appleton Laboratory, Diamond Light Source and Norwegian University of Science and Technology explored the effect of TiB2 and TiC inoculation during solidifciation of a hypereutectic Al-Fe alloy when forming primary Fe-rich intermetallic compound crystals.
Both horizontal, near isothermal conditions and vertical, directional thermal gradient conditions were studied using laboratory and synchrotron X-ray radiography. TiB2 and TiC inoculation enhanced formation of Fe-rich intermetallics under all experimental conditions. Near isothermal solidification resulted in the highest intermetallic number density and average formation rate, whilst increasing the thermal gradient reduced both.
A model for intermetallic crystal formation is proposed (in the paper published in volume 196 of Acta Materialia) to explain the effect of thermal gradient and cooling rate on the intermetallic number density and average formation rate.