Work hardening of mild steel within dynamic strain ageing temperatures

Zeghib, N. E.; Klepaczko, J.R.

doi:10.1007/bf01152163

Cited by 7 publications

(3 citation statements)

References 6 publications

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“…Materials with dynamic strain aging characteristics show a negative strain-rate sensitivity (Zeghib and Klepaczko 1996) The peak of the stress is shifted to higher temperatures when the strain rate increases, while its peak stress decreases. The reason why this phenomenon happens is because the velocity of the dislocations is very high, and not all solutes can follow them for an interaction (Jiang et al 2007).…”

Section: Strain-rate Sensitivitymentioning

confidence: 96%

A dislocation based material model for warm forming simulation

et al. 2008

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Based on experimental results, a dislocation material model describing the influence of dynamic strain aging on the deformation behavior at elevated temperatures is presented. One and two stage loading tests at different temperatures were performed in order to describe the hardening behavior during the deformation at elevated temperatures as well as the hardening behavior after the dynamic strain aging process. Bergström's theory of work hardening was used as a basis for the model development. In the proposed model a relationship between material coefficients of the classical Bergström model and temperature was investigated. The aim of the new material model was to introduce the least possible amount of new parameters as well as to facilitate the mathematical determination of parameters during the fitting of the model with the experimental data. The developed model was implemented in an in-house FE-Code in order to simulate the material behavior due to the dynamic strain aging. Representative simulation results were compared with the experimental data in order to validate the efficiency and the application range of the model. Simulation of the forming process provided data for optimizing strength properties and enabled process control.

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Section: Strain-rate Sensitivitymentioning

confidence: 96%

A dislocation based material model for warm forming simulation

et al. 2008

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“…As discussed previously, dynamic strain aging (DSA) may also cause negative rate sensitivity for different cumulative plastic strain/strain rates/temperature combinations. Zeghib and Klepaczko (1996) in tension tests on low-carbon steel specimens that larger dislocation densities and flow stress have been found in tests during serrated stress flow than those other tests with no serrated stress flow. The increase in dislocation density is believed to be the cause for the increased flow stress.…”

Section: Strain Rate Effects On Stressmentioning

confidence: 66%

“…However, temperatures measured during the D series tests can be considered not high enough to significantly affect the measured flow stress when compared to that for a specimen tested at room temperature (20°C to 30°C). Another possible mechanism which may cause the negative rate sensitivity seen for these specimens loaded at the strain rate higher than 10'2 s '1 is dynamic strain aging (DSA) instead o f due to the temperature rise alone Zeghib and Klepaczko (1996). have noted that DSA can occur at a temperature as low as 75°C for mild steel.Generally, serrations on the stress-strain curve, known as the Portevin-Le Chatelier (PLC) effect, can be seen when DSA occurs.…”

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confidence: 99%