Effect of Temperature and Strain Rate on Dynamic Re-Crystallization of 0.05C- 1.52Cu-1.51Mn Steel

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Mechanics, Materials Science & Engineering, September 2016

ISSN 2412-5954

Effect of Temperature and Strain Rate on Dynamic Re-Crystallization of 0.05C1.52Cu-1.51Mn Steel Pawan Kumar1, a, Peter Hodgson1, b 1

Institute For Frontier Materials, Deakin University, Australia

a

pkumar@deakin.edu.au

b

peter.hodgson1@deakin.edu.au DOI 10.13140/RG.2.1.4905.2403

Keywords: dynamic re-crystallization, strain rate, temperature

ABSTRACT. Dynamic re-crystallization (DRX) is one of the most efficient methods to achieve ultra-fine ferrite grain in the steel. The DRX associated with the formation of new grains in hot working condition. The factors influencing the grain size achievable through thermo-mechanical controlled processing are known to be work hardening and softening by dynamic process of recovery. The point at which the combine effect of strain hardening and recovery are unable to accommodate more immobile dislocation is the starting point of DRX process. In present investigation, critical stress for initiation of DRX is calculated for 0.05C-1.52Cu-1.51Mn steel and the influence of strain rate and temperature is studied. It was observed that at lower strain rate, critical stress for initiation of Dynamic re-crystallization (DRX) is increases initially and then it become saturated at higher strain rate. It is also absorbed that higher temperature and lower strain rates are the favourable condition for typical DRX process. It is also hinted that Cu precipitation take place process adopted in the experiments.

Introduction. Dynamic re-crystallization (DRX) is one of the most efficient method to achieve ultrafine ferrite grain in the steel [1-2]. The DRX associated with the formation of new grains (in hot working condition); the size of grain is expressed as:

where A is a constant; G is the shear modulus; n is the grain size exponent, which is about 0.7 for hot working conditions [3-5]. The factors influencing the grain size achievable through thermo-mechanical controlled processing are known to be work hardening and softening by dynamic process of recovery [6]. The three mechanisms with strain hardening, dynamic recovery and dynamic re-crystallization are different in their softening mechanisms. When the combine effect of strain hardening and recovery are unable to accommodate more immobile dislocation is the starting point of DRX process. Low stacking-fault energy materials generally exhibit discontinuous DRX. The mechanism corresponding to DDRX is bulging (local migration). Bulging of grain boundaries generate nuclei which further grows and consumes at deformed matrix; leading to increase in the dislocation density. The morphology governing by DDRX shows nearly constant average grains size, which is due to the further deforming of large grains due to further straining and taken up by new DRX nuclei. This process considered as a Discontinuous process [7, 8-9]. MMSE Journal. Open Access www.mmse.xyz

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