A physical basis for primary recovery creep

Abstract

Abstract Use is made of a previous suggestion by Webster, Cox and Dorn (1969) in deriving the Garofalo equation for primary creep. It is postulated that the decrease in the driving force for recovery to some steady state value follows first order kinetics. The analysis shows that the rate constant for this reaction can be identified with the primary creep constant, m, obtained from the Garofalo equation. The ideas are applied to the network theory of creep by associating the driving force term with the dislocation line tension. A number of predictions can then be made relating the rate of increase of average mesh size during primary creep. It is shown finally that these predictions are in good quantitative agreement with measurements made on a stainless steel and also with previously published data on iron and an iron—3% silicon alloy.