A Mechanism of Deformation of Metals at High Temperatures with Special Reference to the Tension Test and the Creep Test

Abstract

The three kinds of characteristic functions in the deformation theory of the authors, i.e. strain rate function, work hardening function, and rate of recovery, were determined for 0.14 percent carbon steel from the results of the constant strain rate tension tests at a temperature of 450°C. These functions were compared with those determined from the data of the constant stress creep tests. It was found that the agreement between them was satisfactory. The relations of strain rate to elapsed time in the constant stress creep tests under several stress levels were predicted by the theory using the three characteristic functions determined independently of the results of the creep tests. The predicted relations were in good agreement with the experimental ones. The characteristic functions determined were discussed on the basis of metal physics, and were interpreted from the knowledge of behavior of both dislocations and vacancies. It is concluded that the behavior of the mild steel at high temperatures could be predicted by the present theory, if a proper form of each characteristic function were given.