| The dynamic strain aging effect which had been commonly identified with the serrations on the stress-strain curve, was studied by observing the strain rate sensitivity, if., the stress change due to the sudden change of strain rate during deformation. The new experimental method attempted in this study was to change the strain rate at the same stress and strain on the cyclically stabilized stress-strain curve so that the work hardening effect could be eliminated. The initial stress change and the gradual stress change accompanying the strain rate change were measured seperately identifing the form or with the viscous effect and the latter with the dynamic strain aging effect. The experiment was performed in a relatively large strain rate range of 3.2×10＾(-7) to 3.2×10^(-3) and a temperature range of 20℃ to 800℃. Among the substitutional alloys which were of our interests for the current study, 304 austenitic stainless steel was chosen as a test material because its dynamic strain aging temperature and strain rate ranges could be obtained with our experimental facilities. The main conclusions are that the dynamic strain aging effect could be studied quantitatively and the strain rate change method is very effective for the purpose, and that, for 304 austenitic stainless steel, the dynamic strain aging effect appears most strongly at the strain rates of 10＾(-6), 10＾(-5), 10^(-4) and 10^(-3) for the temperatures of 300℃, 400℃, 500℃, and 600℃, respectively. |
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