Deformability of a SiCw/6061Al composite during high strain rate compression at elevated temperatures

Abstract

The deformability of SiCw/6061Al composite during high strain rate compression has been investigated at elevated temperatures around the solidus of the matrix alloy. The results show that the maximum deformability was obtained at 580°C which is near the solidus of the matrix. Analysis of the results indicates that the composites deformed at 580°C have the largest strain rate sensitivity (m value) and the lowest threshold stress, both of which lead to the maximum deformability. Microstructure observation shows that microcracks were formed at the interfaces in the composites deformed at 540°C and 620°C, whereas, in the composite deformed at 580°C, microcracks were rarely found because of the low stress concentration at the interfaces due to the presence of a small amount of liquid. It is suggested that the presence of an adequate amount of liquid phase gives rise to the effective accommodation required for grain boundary sliding for the composite, and thus directly affects the deformability of SiCw/6061Al composite.