Modified instability condition for identification of unstable metal flow regions in processing maps of magnesium alloys

Babu, N. S.; Tiwari, S. B.; Rao, B. Nageswara

doi:10.1179/174328405x47519

Cited by 21 publications

(7 citation statements)

References 19 publications

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“…These metallic materials are frequently processed by hot rolling or forging, generally at elevated temperatures [5], being necessary to optimize processing parameters for maximum efficiency and workability. Workability or easiness of hot deformation is usually defined as the amount of deformation that a material can undergo without cracking or reaching undesirable conditions at a given temperature and strain rate [6].…”

Section: Introductionmentioning

confidence: 99%

Study of hot deformation of an Al–Cu–Mg alloy using processing maps and microstructural characterization

Cepeda-Jiménez¹,

Ruano²,

Carsí³

et al. 2012

Materials Science and Engineering: A

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The forming behaviour of an Al-Cu-Mg alloy (Al 2024-T351) has been studied by processing maps and microstructural characterization. Torsion tests were conducted in the range 278 to 467 ºC, between 2.1 and 25.6 s-1. Stress-strain curves obtained from the experiment data were fitted using the Garofalo equation to obtain the constitutive parameters, obtaining a stress exponent of 6.1 and an activation energy of 180 kJ/mol. Electron backscatter diffraction (EBSD) was employed to characterize the microtexture and microstructure, before and after torsion testing, to evaluate the microstructural changes and instability phenomena. A peak ductility of the Al 2024 alloy was found at about 400 ºC at all strain rates considered. According to the processing maps and microstructure observation, the optimum hot deformation condition for the Al 2024 alloy is in the range 360-410 ºC and 2.1-4.5 s −1. Under these favourable conditions a uniform and fine grain size is obtained by extended dynamic recovery (DRV), which leads to the formation of subgrain boundaries that progressively transform at large strains into new high angle grain boundaries.

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Section: Introductionmentioning

confidence: 99%

Study of hot deformation of an Al–Cu–Mg alloy using processing maps and microstructural characterization

Cepeda-Jiménez¹,

Ruano²,

Carsí³

et al. 2012

Materials Science and Engineering: A

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“…Such processing maps have been used to study aluminium and magnesium alloys. [3][4][5] The present work focuses on the hot formability of 7020 aluminium alloy. The flow stress curves are obtained from isothermal axisymmetric compression tests using large temperature and strain rate ranges.…”

Section: P~smentioning

confidence: 99%

Analysis of constitutive behaviours and processing map of 7020 aluminium alloy

Liu

Fang

2010

Materials Science and Technology

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The authors present a study on the hot formability of 7020 aluminium alloy. Isothermal hot compression tests of solid cylindrical specimens were performed in the temperature range of 300–550°C and the strain rate range of 0·001–10 s–1. Stress–strain curves obtained from the experiment data are fitted using the Sellars–Tegart constitutive equation to obtain the constitutive parameters. Using the dynamic material model, the authors develop a processing map based on the flow stress data. The map shows that the parameters suitable for hot working are a temperature range of 450–550°C and a strain rate range of 0·001–0·1 s–1. This parameter range is where the efficiency of power dissipation is above 27% and where dynamic recrystallisation occurs. Unstable regions to be avoided in hot forming are deduced from an instability condition. The processing map is validated by comparing the microstructures of deformed compression specimens.

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“…The advantageous feature of the present model with respect to JC model is that it feeds the inputs of compression test only and eliminates the need of torsion test result. Further, the developed relationship has been tagged by a limited number of constants which can be Brought to you by | University of California Authenticated Download Date | 6/9/15 4:39 AM obtained by a simpler computational rout and make it ad vantageous over Babu Model [8].…”

Section: Introductionmentioning

confidence: 99%

Determination of Flow Stress Using Parametric Linearity Relationship of Arrhenius Power Law

Maheshwari

2014

High Temperature Materials and Processes

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In this study, hot workability aspect for model ing the flow stress at specified deformation level is in vestigated. The proposed model contains the basic para metric relationship of Arrhenius power law. The developed mathematical model is validated on Al 2024 alloy to check its feasibility over a wide range of strain rate, strain, and temperature. When compared with JohnsonCook (JC) model, it is found to give a more perceptible experimental output by limited evaluation of arbitrary constants. The proposed model uses the input from hot compression test without the necessacity to go to torsion experiment. This proves its supremacy over JC model which require both the inputs. It also limits the number of constants, so pro duces a forwarding mark to N.S. Babu Model which needs 48 numbers of constants to define the constitutive aspect of deformation.

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Modified instability condition for identification of unstable metal flow regions in processing maps of magnesium alloys

Cited by 21 publications

References 19 publications

Study of hot deformation of an Al–Cu–Mg alloy using processing maps and microstructural characterization

Study of hot deformation of an Al–Cu–Mg alloy using processing maps and microstructural characterization

Analysis of constitutive behaviours and processing map of 7020 aluminium alloy

Determination of Flow Stress Using Parametric Linearity Relationship of Arrhenius Power Law

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