A unified constitutive model based on dislocation density for an Al-Zn-Mg-Cu alloy at time-variant hot deformation conditions

In order to study the flow behaviors of an Al-Zn-Mg-Cu alloy at elevated temperatures, uniaxial tensile tests were carried out in wide deformation temperature and strain rate ranges. The flow stress rapidly increases to a peak value and then slightly decreases with the increased strain, and the dyna...

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Bibliographic Details
Published inMaterials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 718; pp. 165 - 172
Main Authors Lin, Y.C., Dong, Wen-Yong, Zhou, Mi, Wen, Dong-Xu, Chen, Dong-Dong
Format Journal Article
LanguageEnglish
Published Lausanne Elsevier B.V 07.03.2018
Elsevier BV
Subjects
Alloy
Aluminum base alloys
Constitutive model
Constitutive models
Copper
Deformation
Deformation mechanism
Deformation mechanisms
Dislocation density
Flow behavior
Hardening rate
High temperature
Iterative methods
Magnesium base alloys
Mathematical models
Strain rate
Studies
Tensile tests
Work hardening
Yield strength
Zinc
Constitutive model
Flow behavior
Alloy
Deformation mechanism
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Summary:In order to study the flow behaviors of an Al-Zn-Mg-Cu alloy at elevated temperatures, uniaxial tensile tests were carried out in wide deformation temperature and strain rate ranges. The flow stress rapidly increases to a peak value and then slightly decreases with the increased strain, and the dynamic recovery (DRV) is the primary softening mechanism. A unified constitutive model based on dislocation density was developed. An iterative procedure was implemented into the developed model to describe the flow behaviors at time-variant deformation conditions (e.g. the strain rate is changed during hot deformation). The predicted flow stresses were in accord with the experimental results, suggesting that the flow behaviors of the studied Al alloy at elevated temperatures can be well reproduced by the developed model. Meanwhile, the variations of the product of the instantaneous work hardening (WH) rate and stress caused by dislocation evolution, the dislocation density changing rate, as well as the dislocation mean free path, were given to analyze the WH and DRV mechanisms of Al-Zn-Mg-Cu alloy.
ISSN:0921-5093
1873-4936
DOI:10.1016/j.msea.2018.01.109