Study on refine and morphology change of AlFeSi phase in A380 alloy by K addition

Aluminum-Silicon (Al-Si) alloys are one of the most widely used aluminum alloys. But iron can severely deteriorate the mechanical property of Al-Si diecasting alloy because its presence leads to the precipitation of different AlFeSi intermetallic phases which damage the ductility of alloys. Thus controlling the fraction and morphology of AlFeSi phase, especially the (3-AlFeSi phase is important way to refine the ductility of Al-Si die casting alloys. In this article, K element was added into A380 alloys to study the effect of K on the morphology change of AlFeSi phase. The results show that a certain level of K addition 0.05-0.1 wt% will refine beta-AlFeSi and transform P-AlFeSi phase to alpha-AlFeSi. In addition, K addition can better refine AlFeSi at high ccoling rates. The mechanism of refinement of K on AlFeSi phase is analyzed.