Measurement of stored energy in Fe–48%Ni alloys strongly cold-rolled using three approaches: Neutron diffraction, Dillamore and KAM approaches

Betanda, Yanick Ateba; Helbert, Anne‐Laure; Brisset, François; Mathon, Marie‐Hélène; Waeckerlé, Thierry; Baudin, Thierry

doi:10.1016/j.msea.2014.07.037

Cited by 115 publications

(25 citation statements)

References 28 publications

(36 reference statements)

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“…Based on the strain gradient model by Gao et al (1999), the authors define a GND array for a cylinder under torsion. Assuming a series of twist subgrains boundaries in the cylinder, each containing two perpendicular arrays of screw dislocations, the misorientation angle ω ik is related to KAM and the GND density by the following equation (Betanda et al, 2014):…”

Section: Appendix A: Local Misorientation Annexedmentioning

confidence: 99%

Study of recovery and first recrystallisation kinetics in CGO Fe3%Si steels using misorientation‐derived parameters (EBSD)

Cruz-Gandarilla

Bolmaro

Mendoza-Leon

et al. 2019

Journal of Microscopy

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Summary Many metallurgical processes produce characteristic dislocation accumulation, with heterogeneous spatial and orientation distributions and further development of microstructures after heat treatment. Recovery and recrystallisation behaviours are direct consequences of those uneven dislocation distributions. The Electron BackScatter Diffraction (EBSD) technique can be used for the characterisation of such microstructural features, including: Density of Geometrically Necessary Dislocations (GND), Kernel Average Misorientations (KAM), Grain Orientation Spread (GOS), Grain Average Misorientation (GAM), Grain Reference Orientation Deviation (GROD – Angle) and GOS/D, where D is an assumed characteristic grain length. Production of Fe3%Si alloys with a Goss texture, essential step in the manufacture of electrical transformers, requires several different processing stages, including the one called primary recrystallisation, a key process preceding abnormal grain growth. The structure of grains and different microstructural aspects of the recrystallisation stage will provide the conditions for development of the Goss orientation during abnormal grain growth. In the present work we use GOS, GAM, GROD, GOS/D, GND and KAM, calculated from EBSD scans performed on cold rolled Fe3%Si alloys subject to increasing heat treatment times, to characterise the kinetics of recovery and primary recrystallisation in an Fe3%Si alloy. Difficulties in the interpretation of these results may arise from the interactive competition between various microstructural features. Hardness measurements were also performed in order to validate recovery and recrystallisation evolution by classical methods. It was found that the global GOS (i.e. including grains of all orientations) shows changes which can be related to those observed in the hardness for high annealing temperatures but it is not sensitive to microstructure evolution occurring at low temperatures. Meanwhile, GND undergoes changes at all annealing temperatures and, remarkably, it responds to the recovery that GOS cannot detect at low temperatures. The GAM parameter seems to follow better the microhardness results. When grains belonging to different texture components are analysed, gamma fibre grains are the first to recrystallise and alpha fibre grains the last. Lay Description Many metallurgical processes produce characteristic dislocation accumulation, with heterogeneous spatial and orientation distributions. Further development of such microstructures occurs with subsequent heat treatments. Recovery and recrystallisation behaviours are directly affected by consequences of those uneven dislocation distributions. The Electron Back Scatter Diffraction (EBSD) technique can be used for the characterisation of such microstructural features using different magnitudes that describe locally or globally misorientations between various locations in the material. In search of the best parameters [among them: Density of Geometrically Necessary Dislocations (GND), Kernel Average Misorientatio...

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Section: Appendix A: Local Misorientation Annexedmentioning

confidence: 99%

Study of recovery and first recrystallisation kinetics in CGO Fe3%Si steels using misorientation‐derived parameters (EBSD)

Cruz-Gandarilla

Bolmaro

Mendoza-Leon

et al. 2019

Journal of Microscopy

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“…From Figure 4d-f, the local misorientations of the outer zone and inner zone were around 2 • , while the local misorientation of the center zone was around 1 • . Betanda et al [27] reported that local misorientation distribution maps are an effective indicator of local strain in crystal materials. Therefore, the difference in the local misorientation also confirmed the occurrence of strain heterogeneity.…”

Section: Deformation Microstructure Of the Dp Steelmentioning

confidence: 99%

The Impact of Strain Heterogeneity and Transformation of Metastable Austenite on Springback Behavior in Quenching and Partitioning Steel

Liu

et al. 2018

Metals

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Multiple strengthening methods, such as high dislocation density, high twin density, small grain size, and metastable austenite phase can give high strength to ultra-high strength steels (UHSSs). However, the high strength of UHSSs often results in a greater tendency for springback when applied in manufacturing vehicle components. In the present study, two types of UHSSs, dual-phase (DP) steel and quenching and partitioning (QP) steel are investigated to study the springback behavior during the bending process. Results indicated that both the strain heterogeneity and the transformation of retained austenite impacted the springback behavior. The springback angle of the DP steel increased with the increase in bending angle, which was caused by the increasing degree of strain heterogeneity. However, the springback angle of the QP steel decreased to a 14.75 • when QP specimens were strained at a 104 • bending angle due to the inhibiting effect of the phase transformation. This indicated that there was preferential phase transformation in the thickness direction in the retained austenite of the outer and inner zones. The phase transformation caused low strain heterogeneity, which resulted in a lower tendency for springback. The results suggested that QP steel could possess lower springback at a proper bending angle.

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“…Dislocations are comprised of geometrically necessary dislocations (GND) and statistically stored dislocation (SSD); GNDs are dislocations with the same signs which are formed in the strain gradient region and satisfy the geometrical constraints with a net non-zero Burgers vector, whereas SSDs constitutes random dislocations formed by mutual trapping process with a net zero Burgers vector during plastic deformation [26,[31][32][33][34]. According to Ashby's model for homogenous deformation of a single crystal, SSD have dominant role in work hardening.…”

Section: Introductionmentioning

confidence: 99%

“…Upon cooling, the sample temperature was stabilised at 200 o C to maintain thermal equilibrium and to minimise the thermal drift [14]. For post processing of the EBSD results, files were exported into HKL [26,32,47] to understand the difference in rate of recrystallization of respective fibres during annealing at different conditions [7,14,[28][29][30]. To evaluate a noise free GND density, the LAM value of all points were calculated and plotted based on a kernel size of 11x11 (n=5) to 3x3 (n=1) as described by Moussa et al [48].…”

Section: Introductionmentioning

confidence: 99%

Quasi in-situ analysis of geometrically necessary dislocation density in α-fibre and γ-fibre during static recrystallization in cold-rolled low-carbon Ti-V bearing microalloyed steel

Kapoor

Lan

Rijkenberg

et al. 2018

Materials Characterization

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NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/. Publisher's statement:Please refer to the repository item page, publisher's statement section, for further information.For more information, please contact the WRAP Team at: wrap@warwick.ac.uk.Quasi in-situ analysis of geometrically necessary dislocation density in α-fibre and γ-fibre during static recrystallization in cold-rolled low-carbon Ti-V bearing microalloyed steel Abstract In the present study, cold-rolled low-carbon steel is annealed at three different conditions: 700 o C for 0 s, 800 o C for 0 s and 800 o C for 2 min at the heating rate of ~10 o C/s. Recrystallization behaviour on sample surface is studied using a heated stage Scanning Electron Microscopy and Electron Backscattered Diffraction. For the lower annealing temperature of 700 o C with no dwell, almost no recrystallization is observed and microstructure resembles the as-received deformed material with the exception of occasional sub-micron sized nuclei. For the annealing conditions of 800 o C 0 s and 800 o C 2 min, onset and evolution of recrystallization is observed in-situ as a function of the initial as-cold rolled texture. Slower recovery rate of alpha fibre than gamma fibre is observed and confirmed by lower drop in average geometrically necessary dislocation (GND) density for un-recrystallized alpha fibres(1.1E+14 m -2 for 700 o C 0 s , 1.4E+14 m -2 for 800 o C 0 s and 4.5E+14 m -2 for 800 o C 2 min) than for un-recrystallized gamma fibre grains (3.0E+14 m -2 for 700 o C 0 s , 6.2E+14 m -2 for 800 o C 0 s and 9.8E+14 m -2 for 800 o C 2 min) during annealing. Strong gamma texture in recrystallized matrix is found for annealing conditions of 800 o C 0 s and 800 o C 2 min. From TEM characterisation it was shown that sub-grain boundaries are decorated with fine precipitates (diameter d < 15 nm) of titanium-vanadium carbides (Ti,V)C for the annealing condition of 700 o C 0 s, which suggests that these precipitates play a major overall role in retardation of the recrystallization kinetics.

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Measurement of stored energy in Fe–48%Ni alloys strongly cold-rolled using three approaches: Neutron diffraction, Dillamore and KAM approaches

Cited by 115 publications

References 28 publications

Study of recovery and first recrystallisation kinetics in CGO Fe3%Si steels using misorientation‐derived parameters (EBSD)

Study of recovery and first recrystallisation kinetics in CGO Fe3%Si steels using misorientation‐derived parameters (EBSD)

The Impact of Strain Heterogeneity and Transformation of Metastable Austenite on Springback Behavior in Quenching and Partitioning Steel

Quasi in-situ analysis of geometrically necessary dislocation density in α-fibre and γ-fibre during static recrystallization in cold-rolled low-carbon Ti-V bearing microalloyed steel

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