Dynamic recrystallization in nickel and nickel-iron alloys during high temperature deformation

Luton, M.J.; Sellars, C. M.

doi:10.1016/0001-6160(69)90049-2

Cited by 549 publications

(247 citation statements)

References 11 publications

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“…5) cannot be explained in terms of discontinuous or geomet-ric dynamic recrystallization. This is because neither signal of grain boundary migration nor serrated grain boundaries are observed in the deformed microstructures [37][38][39][40][41]. Moreover, deformation shear bands associated with adiabatic heating are not observed under the testing conditions of this study, which generally should produce softening [42].…”

Section: Hot Deformation Behaviormentioning

confidence: 70%

“…For example, it has been reported in several studies that the substructure develops during the early stages of deformation up to the peak stress [6,51,52]. By contrast, it has been concluded in an early study that subgrain boundaries in Al do not form until p is reached [38,53]. Furthermore, new subgrains were not developed in a 6061 Al alloy until certain strain beyond the peak stress was attained [24].…”

Section: Hot Deformation Behaviormentioning

confidence: 99%

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Microstructure gradient after hot torsion deformation of powder metallurgical 6061 Al alloy

Eddahbi

Borrego

Monge

et al. 2012

Materials Science and Engineering: A

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Abstract:The microstructure and the texture of extruded 6061 Al alloy processed by powder metallurgy (PM), using three different initial powder particle sizes, have been studied after torsion deformation at 300 • C at strain rate of 6 s −1 . The initial extruded microstructure of the three alloys consisted of elongated grains confining substructure with a typical 1 1 1 + 1 0 0 fiber texture. After torsion deformation, the torque ( ) as a function of the equivalent strain (ε eq ) showed softening and the microstructure exhibited a gradient across the section so that the inner and outer zones contained sheared-elongated and small-equiaxed subgrains, respectively. It was observed that the equivalent strain to failure for the material processed using powder particles size of less than 45 m was of about ε eq ∼ 12, compared to ε eq ∼ 1 for material processed using powder particles size of less than 25 m. The microstructural changes during hot torsion deformation of PM 6061 Al alloy should involve continuous dynamic processes.

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Section: Hot Deformation Behaviormentioning

confidence: 70%

Section: Hot Deformation Behaviormentioning

confidence: 99%

Microstructure gradient after hot torsion deformation of powder metallurgical 6061 Al alloy

Eddahbi

Borrego

Monge

et al. 2012

Materials Science and Engineering: A

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“…In the past, most predictive models are based on either modified Johnson-Mehl-Avrami kinetic equations or probabilistic approaches. [13][14][15][16][17][18][19][20] In this work, a DDE is used for modeling this type of stress-strain behavior: a delay time due to diffusion is taken into consideration, and it is expressed in terms of a critical strain for nucleation for recrystallization.…”

Section: A Oscillatory Flow Behavior During Hot Workingmentioning

confidence: 99%

“…In their classic work, [13] Luton and Sellars correctly proposed that multiple stress peaks should appear when the ratio of the characteristic strain for nucleation of recrystallization, e n , to the characteristic strain for completion of recrystallization, e x , is large. If x/h is taken to be e x on the basis that h is a high-temperature modulus and x is a steady-state stress, the ratio, e n/ e x , is then equivalent to k = he n /x.…”

Section: ½11mentioning

confidence: 99%

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On Cyclical Phase Transformations in Driven Alloy Systems

Lee

2007

Metall Mater Trans A

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Cyclical phase transformations occurring in driven materials syntheses such as ball milling are described in terms of a free energy minimization process of participant phases. The oscillatory flow behavior of metals with low stacking fault energies during hot working is taken as a prototype in which a ductile crystalline phase sustains undulation in its free energy, due to the alternate succession of work-hardening and work-softening mechanisms. A time-dependent, oscillatory free energy function is then obtained by solving a delay differential equation (DDE), which accounts for a time lag due to diffusion. To understand cyclical transitions on an atomistic scale, work is extended to molecular dynamics simulations. Under shear deformation, a two-dimensional nanocrystal shows cyclical transitions between an equilibrium rhombus and a nonequilibrium square phase. Three-dimensional simulations show crystalline-to-glass transitions at high strain rates, but very high shear strain rates are found to lead to a latticelike network structure in the plane perpendicular to the shear direction, with strings of atoms parallel to the shear direction.

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From transient to steady state deformation and grain size: A thermodynamic approach using elasto-visco-plastic numerical modeling

Herwegh

Poulet

Karrech

et al. 2014

J. Geophys. Res. Solid Earth

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Numerical simulation experiments give insight into the evolving energy partitioning during high-strain torsion experiments of calcite. Our numerical experiments are designed to derive a generic macroscopic grain size sensitive flow law capable of describing the full evolution from the transient regime to steady state. The transient regime is crucial for understanding the importance of microstructural processes that may lead to strain localization phenomena in deforming materials. This is particularly important in geological and geodynamic applications where the phenomenon of strain localization happens outside the time frame that can be observed under controlled laboratory conditions. Our method is based on an extension of the paleowattmeter approach to the transient regime. We add an empirical hardening law using the Ramberg-Osgood approximation and assess the experiments by an evolution test function of stored over dissipated energy (lambda factor). Parameter studies of, strain hardening, dislocation creep parameter, strain rates, temperature, and lambda factor as well as mesh sensitivity are presented to explore the sensitivity of the newly derived transient/steady state flow law. Our analysis can be seen as one of the first steps in a hybrid computational-laboratory-field modeling workflow. The analysis could be improved through independent verifications by thermographic analysis in physical laboratory experiments to independently assess lambda factor evolution under laboratory conditions.

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Dynamic recrystallization in nickel and nickel-iron alloys during high temperature deformation

Cited by 549 publications

References 11 publications

Microstructure gradient after hot torsion deformation of powder metallurgical 6061 Al alloy

Microstructure gradient after hot torsion deformation of powder metallurgical 6061 Al alloy

On Cyclical Phase Transformations in Driven Alloy Systems

From transient to steady state deformation and grain size: A thermodynamic approach using elasto-visco-plastic numerical modeling

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