Abstract
It is shown that cavity formation in copper is proportional to strain in the primary as well as in the secondary creep range. This proportionality is used in conjunction with the prediction of a constant rate of cavity growth by vacancy condensation, when cavities are widely spaced compared with their size, to indicate a volume increase due to cavitation which is proportional to the product of creep strain and time independently of the precise form of creep curve. This relationship is supported by experimental data in the early stages of creep.