Abstract
In this study, the interaction between plasticity and creep deformation is observed from both macro and microscopic point of view using Type 304 stainless steel at room temperature. The experiments conducted in this study are as follows: (1) subsequent creep after tension-compression cyclic preloading with a constant strain amplitude under a constant strain rate; (2) subsequent torsional creep after cyclic torsional preloading with a constant strain amplitude under a constant strain rate; (3) subsequent stress relaxation tests after tension-compression cyclic preloading with a constant strain amplitude under a constant strain rate; (4) tension-compression cyclic loading with the change of the strain rate. These experimental results show that the subsequent time-dependent deformations are depending on the number of cycles of the preloading even though the stress-strain curves of the preloading are almost same. To verify the difference from microscopic point of view transmission electron microscope (TEM) observations are conducted. The dislocation structures observed are clearly different due to the number of cycle of the preloading.
