The Mechanism of Cavitation in Copper during Creep

Abstract

AbstractAbstractDuring creep of copper, cavities form on grain boundaries and cause a decrease in density. The fractional change in density during creep is proportional to (time)1.5, in reasonable agreement with previous work. Cavities are nucleated continuously during creep, the number present being proportional to (time)0.5. The results suggest that an individual cavity increases its volume at a constant rate in keeping with a growth mechanism that involves diffusion of vacancies along the grain boundary to the cavity surface. When tensile creep specimens are compressed slowly at 400° C or at room temperature the density increases by similar amounts, suggesting that sintering does not occur by reversed grain-boundary sliding. The cavities formed by creep become stabilized by the diffusion of gas into them.