A Theory of Plastic Deformation of Metals at High Temperatures : (IV) Creep Behaviour of Mild Steel after a Sudden Change in Stress

Abstract

Mechanisms of work hardening and recovery following an abrupt change in stress were discussed on the basis of the behaviour of dislocations. It was suggested that there would be a mechanism, which might act as a mechanism of recovery when the applied stress was abruptly decreased, while it might act as a mechanism of work hardening when the applied stress was suddenly increased. A mathematical expression of this mechanism was determined in a rather simpler form from the data of creep tests with sudden change in stress. Using this expression as well as other characteristic functions, which have been determined from the results of tension tests and creep tests with a duration of stress rest, it was also shown that the authors' theory of deformation well predicted the behaviour of mild steel after a sudden change in stress in primary or secondary stage of creep.