Cavity Growth by Grain-Boundary Sliding during Creep of Copper

Abstract

Cavities were developed on the grain boundaries of oxygen-free, high-conductivity copper specimens deformed to the tertiary stage of creep in tension at 415° C. Subsequently, the specimens were deformed in compression at either 90° or 180° to the original stress direction, both at room temperature and at 415° C. Density measurements and metallographic examination after compression indicate that further cavity growth occurs only when the compressive strain is applied at 90° to the original tensile stress and at 415° C. This is considered to show that grain-boundary sliding plays a predominant role in the growth of cavities during creep.