摘要

Inclusions, particularly clusters of inclusions, in aluminum castings can seriously degrade machining performance. The characteristics of inclusion cluster in the Al-Si-Cu die casting cylinder blocks for air compressors are investigated by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The results show that there are two main types of inclusions including aluminum oxides and aluminum carbides in cluster. The hardness ranges from 818.1 HV to 1425.7 HV within cluster, which is about 8 to 14 times higher than that of aluminum alloy. The factors regarding casting process affecting the cluster formation are discussed.