The kinetics of dynamic recrystallization and construction of constitutive modeling of RAFM steel in the hot deformation process

To investigate the effect of equal channel angular pressing (ECAP) on the deformation of Ti-6Al-4V alloy at a higher temperature, hot compression tests were conducted on alloys having two different initial microstructures (the original alloy (Pre-ECAP) and ECAP-deformed alloy (Post-ECAP)). Post-ECAP, the alloy showed a higher degree of dynamic softening during the hot deformation process due to its finer grain size and higher distortion energy. The flow stress of Post-ECAP alloy was higher than the Pre-ECAP alloy at 500 °C when ε˙= 0.003 s−1. However, the stress of the Post-ECAP alloy decreased rapidly with increasing temperature and strain rate, until the stress value was much lower than that of Pre-ECAP at 700 °C when ε˙= 0.03 s−1. The value of the dynamic softening coefficient revealed that the dynamic softening behavior of Post-ECAP was more pronounced than that of Pre-ECAP in the hot compression deformation process. The main dynamic softening mechanism of Pre-ECAP is dynamic recovery, while the dynamic recrystallization process plays a more important role in the deformation process of Post-ECAP alloy. The microstructures observation results showed that dynamic recrystallization was more likely to occur to Post-ECAP alloys under the same deformation condition. Almost fully dynamic recrystallization had occurred in the deformation process of Post-ECAP at 700 °C and a strain rate of ε˙= 0.01 s−1. The grains of Post-ECAP alloys were further refined. The Post-ECAP alloy exhibits better plastic deformation at temperatures higher than 600 °C due to its significant dynamic recrystallization.

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Modified kinetic model for describing continuous dynamic recrystallization behavior of Al 2219 alloy during hot deformation process

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2019.153301 ◽

2020 ◽

Vol 817 ◽

pp. 153301 ◽

Cited By ~ 8

Author(s):

Lei Liu ◽

Yunxin Wu ◽

Hai Gong ◽

Fang Dong ◽

A.S. Ahmad

Keyword(s):

Kinetic Model ◽

Dynamic Recrystallization ◽

Hot Deformation ◽

Deformation Process ◽

Recrystallization Behavior ◽

Continuous Dynamic Recrystallization ◽

Dynamic Recrystallization Behavior ◽

Continuous Dynamic

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Constitutive modeling and prediction of hot deformation flow stress under dynamic recrystallization conditions

Mechanics of Materials ◽

10.1016/j.mechmat.2015.02.014 ◽

2015 ◽

Vol 85 ◽

pp. 66-79 ◽

Cited By ~ 64

Author(s):

Hamed Mirzadeh

Keyword(s):

Flow Stress ◽

Dynamic Recrystallization ◽

Constitutive Modeling ◽

Hot Deformation ◽

Modeling And Prediction

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The Influence of Chemical Composition on the Kinetics of Dynamic Recrystallization of IF Austenite

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.1193 ◽

2004 ◽

Vol 467-470 ◽

pp. 1193-1198

Author(s):

Roney Eduardo Lino ◽

Ronaldo Barbosa

Keyword(s):

Activation Energy ◽

Chemical Composition ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Apparent Activation Energy ◽

Hot Deformation ◽

Empirical Expression ◽

Softening Mechanism ◽

Points Of View ◽

Kinetics Of

Dynamic recrystallization, DRX, has become an increasingly important softening mechanism both from fundamental and industrial points of view. During finishing rolling of strips or wire rods, strain is accumulated from pass to pass so that DRX can be triggered. The time need for 50% of material to recrystallize, t50DRX, is strongly dependent on temperature and to a lesser extent on strain rate at which deformation occurs. Few studies report results on the kinetics of DRX and how this softening mechanism can be predicted for a given set of hot deformation conditions, namely strain, strain rate and pass temperature. The purpose of this paper was to investigate how the chemical composition of IF austenite can affect the kinetics of DRX by measuring the apparent activation energy for DRX, QDRX, for alloys with additions of Ti and a combination of Ti-Nb contents. Predicted and measured values of t50DRX, were compared and an empirical expression was proposed to model measured values.

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