Abstract:The effect of velocity on the dry sliding friction and wear characteristics of SiCp/A356 composite was investigated in detail on UMT-2 tribometer. The high temperature friction and wear behavior of the composite were analyzed by SEM, EDS and Olympus confocal laser scanning microscope. The results reveal that the wear rate of as-cast material is increased greatly and its friction coefficient fluctuates within a large range. On the contrary, the increasing degree of the wear rate and the friction coefficient of T6 material is low, which shows excellent friction behavior. the oxidation wear and stripping wear at low velocity of as-cast material is mainly shifted to adhesive wear at high velocity. However, the oxidation wear at low velocity of T6 material is mainly shifted to stripping wear and adrasive wear at high velocity. At high velocity, the crack appears obviously in the cross-section of worn surface of as-cast material, but there are only simple grinding traces and particle shedding in T6 material. Therefore, high temperature wear resistance of the composite has been improved significantly after heat treatment.