Investigation of solidification behavior in aluminum alloys by synchrotron radiation X-ray

Solidification process of materials, specifically real-time observation of dynamic processes during the formation of aluminum alloys at the interface of solid-liquid phases in the present case, was investigated using time-resolved X-ray absorption imaging method which is available in the Spring-8 facility. X-ray fluorecsence (XRF) multiple-elemental analysis using micro-beams was also applied to the present study to determine trace amounts of impurities contained in the aluminum alloys. The method depends on the different absorption coefficient (mass attenuation) of different atoms (for example, Al-Si alloys containing Fe, Cu or Zr) of the specific energy of monochromatic X-rays employed (from 10 to 20 keV). Dendrite arm spacing and its fragmentation process was clearly observed, the results of which were found to be useful to clarify the solidification mechanism. (S. Ohno)