The test conditions (i.e. the test temperature and the strain rate) at which dynamic strain aging takes place during strain-controlled fatigue deformation in type 304 austenitic stainless steel were studied. When the strain rate was low (i.e. 5 × 10-4 - 1.7 × 10-3 s-1), the lower critical temperature for the appearance of serrations during fatigue deformation was much lower than that during monotonic tensile deformation. This result was considered to be caused by the longer arrest time of dislocations in fatigue deformation in comparison with that in monotonic tensile deformation. In such an arrest time the dislocations are locked by solute atoms. The longer arrest time in fatigue deformation is considered to be closely related to the cell-shuttling motion of dislocations in the saturated stress stage of the fatigue process.
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