Complex Modification of Hypereutectic Al-Si Alloy by a New Al-Y-P Master Alloy

In this article, a novel Al-6Y-2P master alloy with cubic YP particles was successfully synthesized and its complex modification performance on Al-18Si alloy has also been investigated. With the doping of La and Ce, (YxLa1-x)P and (YxCe1-x)P particles still exhibit cubic morphologies in three dimensional spaces (3-D space). The excellent complex modification of Al-18Si alloy can be obtained with the addition of Al-6Y-2P master alloy. Under the optimized conditions, i.e. melting temperature of 780 degrees C, addition level of 1.5 wt% and holding time of 30-60 min, the tensile strength and Brinell hardness of Al-18Si alloys can be significantly increased by 16.8% and 17.1%, respectively. It is proposed that the Si atoms in the melt could promote the structure evolution of YP to AlP with the release of Y, which would be reason for the excellent composite modification performance of the developed Al-6Y-2P master alloy.