Invalidation of KBF4 modification on the primary Mg2Si in Mg-Si alloys by Al addition

Addition of Al can lead to the invalidation of KBF4 modification on the primary Mg2Si in Mg-5Si alloys and thus promote the preferred growth of the primary Mg2Si dendrite crystal. This may be due to the decrease or exhaustion of B in the melts by the formation of AlBx.