The modification effect of CX-type (CX means the modifiers that have long effective term) modifiers applied in ZL108 and ZL104 Al-Si alloys has been studied in detail. The results show that the morphologies of the eutectic silicon and the primary silicon can be modified and refined simultaneously. The modification effect acts quickly and can maintain a period of 8 h by the CX-type modifiers. The CX-type modifiers increase the mechanical properties of Al-Si alloys and improve the service properties of machine parts made of Al-Si alloys (such as piston and cylinder etc.). In modifying processes, the amount of the addition of CX-type modifiers is smaller than that of any other modifiers, and the modifying procedures are simple. There are no smoke, no dust, and no irritant smell in modifying processes using CX-type modifiers. Therefore, the CX-type modifiers have advantages in economy and environment protection.
