On grain refinement and titanium segregation in Al-Si alloy

The influence of holding time and distance from sample bottom on segregation and grain refinement of Ti was studied. Results show that Al-5Ti-1B has an obvious effect on refinement in Al-Si alloy after 4 h holding time. The segregation of Ti shows different morphology at different positions of casting. More segregation is at the bottom of castings because of localized congregation of Ti. The research shows that the difference in Ti concentration is as high as 25.6% between the top and bottom of castings.