X-ray nano-diffraction study of Sr intermetallic phase during solidification of Al-Si hypoeutectic alloy

The evolution of strontium (Sr) containing intermetallic phase in the eutectic reaction of Sr-modified Al-Si hypoeutectic alloy was studied with high energy synchrotron beam source for nano-diffraction experiments and x-ray fluorescence elemental mapping. Contrary to popular belief, Sr does not seem to interfere with the Twin Plane Re-entrant Edge (TPRE) growth mechanism of eutectic Si, but evolves as the Al2Si2Sr phase during the eutectic reaction at the boundary between the eutectic Si and Al grains.