Abstract
Surface modified Al-Si sintered alloy by diamond like carbon (DLC) coating surface modification was investigated into the property of the fatigue brittle fracture. By DLC coating, fatigue strength of Al-Si sintered alloy was improved. The strength in the interface between the Al matrix and Si-particle, resistance to crack initiation, was improved. The main factors were as follows. (1) The defects in the surface were healed because the surface was covered with DLC film. (2) In DLC coating material, the debonding on Si-particle was inside crack. The stress intensity factor was lower than that of virgin material. (3) The debonding on Si-particle was controlled by the compressive residual stress on DLC film. This compressive stress gradually hardened the surface of material, and controlled the crack growth.
