| An investigation was carried out on the grain refinement mechanism in pure aluminum, using an ultrasonic detection system, and metallography tests. In this investigation the capability of the ultrasonic detection system in the grain refinement process was studied. The results show that the ultrasonic system, which effectively detects particles larger than 20mum in size, cannot detect the nucleants in the melt, but detects the movements and any cause of floating the particles, which provide more nucleants for the process. In the grain refinement process, the results show that there are other factors influencing the mechanism of grain refinement and fading phenomena, rather than TiAl3 particles. Metastable phases containing titanium can play an important role in preventing the fading phenomena. |
