Effects of hardening and localization of strain in strain aging of technical purity iron
The hardening effect in strain aging of technical purity iron increases with an increase in the degree of preliminary strain by tension (by increasing the density of introduced dislocations) regardless of the character of strain distribution in the sample if the aging time is sufficient for occurrence of hardening according to the “stopper” mechanism.
With nonuniform strain distribution in the sample (completion of preliminary strain within the limits of the yield plateau or with the formation of a neck) there is observed the phenomenon of “geometric loss of strength,” which is presumably related to an increase in the effective value of the stress concentration factor in aging and is especially marked in short aging (comparatively weak blocking of dislocations).
Intensification of strain hardening in strain aging is accompanied by strengthening of the tendency of strain aged technical purity iron toward localization of strain, which does not contradict the classical equations of Konsider and Hart.
Equations were obtained making it possible to describe the influence of strain aging on localization of strain in uniaxial tension.
KeywordsIron Classical Equation Stress Concentration Stopper Aging Time
Unable to display preview. Download preview PDF.
- 1.V. K. Babich, Yu. P. Gul', and I. E. Dolzhenkov, Strain Aging of Steel [in Russian], Metallurgiya, Moscow (1972).Google Scholar
- 2.Yu. P. Gul' and Yu. A. Krishtal, “The influence of the degree of strain on the effect of strain aging of low carbon steel,” in: Interaction between Dislocations and Impurity Atoms in Metals and Alloys [in Russian], Tula Polytechnic Inst. (1969), pp. 226–234.Google Scholar
- 3.Yu. P. Gul', “The influence of the degree of preliminary strain on hardening of technical purity iron in natural aging,” Probl. Prochn., No. 5, 94–97 (1971).Google Scholar
- 4.M. S. Blanter, V. N. Marchenko, and L. A. Metashop, “One feature of the tensile curve of iron after strain aging,” Fiz. Met. Metalloved.,24, No. 4, 764–765 (1967).Google Scholar
- 5.D. Mak Lin, The Mechanical Properties of Metals [in Russian], Metallurgiya, Moscow (1965).Google Scholar
- 6.Yu. P. Gul' and Yu. A. Krishtal, “The role of interaction of dislocations in the strain aging effect of iron,” Fiz.-Khim. Obrab. Met., No. 1, 73–78 (1972).Google Scholar
- 7.Yu. P. Gul', “Physical aspects of embrittlement of strain aged steel,” in: The Physics of Fracture. Summaries of Papers for the Fourth All-Union Conference [in Russian], Part 1, Inst. Probl. Materialovedenie, Kiev (1980), pp. 171–172.Google Scholar
- 8.K. F. Starodubov, Yu. P. Gul', and V. S. Siukhina, “The influence of heat treatment on the kinetics of strain aging of low-carbon steel,” in: Interaction between Dislocations and Impurity Atoms in Metals and Alloys [in Russian], Tula Polytechnic Inst. (1969), pp. 194–204.Google Scholar
- 9.J. J. Jonas, R. A. Holt, and C. E. Coleman, “Plastic stability in tension and compression,” Acta Met.,24, No. 10, 911–918 (1976).Google Scholar
- 10.E. W. Hart, “Theory of the tensile test,” Acta. Met.,15, No. 2, 351–355 (1967).Google Scholar