A Combination of In Situ Synchrotron Diffraction and In Situ Synchrotron Tomography Techniques to Study the Solidification Behaviour of Mg-5Nd-5Zn Alloy


In this work, a combination of in situ experiments; synchrotron diffraction and synchrotron tomography were used to study the solidification behaviour of Mg-5Nd-5Zn (wt. %). The samples were cooled with a cooling rate of 100 °C/min and 5 °C/min in the in situ synchrotron diffraction experiment and in situ synchrotron tomography experiments respectively. The results from synchrotron diffraction experiments provided information regarding phase formation temperature and phase identification. From these results, two intermetallic phases, Mg3(Nd,Zn) and Mg50Nd8Zn42 were identified. The phases identified by the synchrotron diffraction technique were verified with the results from transmission electron microscopy (TEM) observations. Synchrotron tomography results showed that the volume fraction of α- Mg increased and interdendritics decreased as solidification progressed, and pores formed at the end of solidification. From synchrotron tomography, it was also found that interdendritic interconnectivity decreased as the end of solidification approached. The α-Mg interconnectivity was constantly at unity value throughout solidification. The grain coherency temperature was estimated by both techniques – it was estimated to be approximately 535 °C and 540 °C by synchrotron diffraction and tomography respectively.
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