Characterization of Creep Deformation Mechanism and Evaluation of Dislocation Mobility of Modified 9Cr-1Mo Steel by Stress Change Test

In order to characterize the creep deformation mechanism of a Modified 9Cr-1Mo Steel, stress change tests were conducted during creep test. It was confirmed that the dislocation behavior during the creep test was in a viscous manner, since instant plastic strains were not observed at stress change tests. Also we obtained the mobility of dislocation by comparing the observed backward creep behavior after a stress reduction with the analysis which was based on the idea that the bakward behavior was caused with the back-motion of bow-out dislocations in a viscous manner. The analyzed dislocation mobility was in good agreement with the theoretical one.