EFFECTS OF DAMAGE ON THE FLOW STRENGTH AND DUCTILITY OF A DUCTILE AL-ALLOY REINFORCED WITH SIC PARTICULATES

The processing and mechanical properties of an Al alloy reinforced with a high volume fraction of SiC particulates have been investigated. The properties are shown to be appreciably affected by the particle size. These effects have been exclusively related to the incidence of damage caused by the particulates. In particular, particle cracking has been shown to occur in the larger particles, with a cracking probability that increases as the particle size increases. The cracks reduce the flow strength of the materials and crack coalescence controls the ultimate strength and ductility. The measured trends in these properties are in qualitative accordance with simple damage models.