Deformation and fracture behaviour of high manganese austenitic steel
TL;DR: In this article, the deformation behavior of high manganese austenitic Hadfield steel sheet samples was studied under uniaxial tensile test conditions and the effect of temperature on the tensile behaviour and fracture appearance was also studied using the scanning and transmission electron microscopes.
About: This article is published in Journal of Materials Processing Technology.The article was published on 2004-04-10. It has received 134 citations till now. The article focuses on the topics: Strain hardening exponent & Work hardening.
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TL;DR: A review of the relations between microstructure and mechanical properties is presented in this article focusing on plasticity mechanisms, strain-hardening, yield stress, texture, fracture and fatigue.
Abstract: A significant increase in the research activity dedicated to high manganese TWIP steels has occurred during the past five years, motivated by the breakthrough combination of strength and ductility possessed by these alloys. Here a review of the relations between microstructure and mechanical properties is presented focusing on plasticity mechanisms, strain-hardening, yield stress, texture, fracture and fatigue. This summarized knowledge explains why TWIP steel metallurgy is currently a topic of great practical interest and fundamental importance. Finally, this publication indicates some of the main avenues for future investigations required in order to sustain the quality and the dynamism in this field.
1,114 citations
TL;DR: In this article, the thermo-mechanical properties of low stacking fault energy austenitic Fe18Mn0.6C steel exhibiting twinning-induced plasticity were investigated using infrared thermography.
Abstract: The thermo-mechanical properties of low stacking fault energy austenitic Fe18Mn0.6C steel exhibiting twinning-induced plasticity were investigated during uniaxial tensile deformation using infrared thermography. Over a wide strain range, the plastic deformation was by the movement of very few well-defined localized deformation bands. The formation and propagation of Portevin–LeChatelier (PLC) bands lead to type A and type B serrated stress–strain curves, exhibiting a negative strain rate sensitivity. The PLC band properties were analyzed in detail: strain, strain rate and mobile dislocation density within the bands were determined. The microstructures of the un-deformed and deformed Fe18Mn0.6C TWIP steel were studied by transmission electron microscopy. The possible dynamic strain aging processes causing the localized deformation are reviewed.
261 citations
TL;DR: In this article, the authors extend the notion of phase transformations to periodic cellular materials by introducing materials whose unit cells have multiple stable configurations, each stable configuration corresponds to a stable phase, and transitions between these phases are regarded as phase transformations of the cellular material.
230 citations
15 Dec 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a modified Crussard-Jaoul (C-J) analysis and microstructural observations were used to investigate the strain hardening behavior of a Fe-18Mn-0.6C-1.5Al TWIP steel.
Abstract: The strain hardening behavior of a Fe–18Mn–0.6C–1.5Al TWIP steel was investigated through the modified Crussard–Jaoul (C–J) analysis and microstructural observations. The strain hardening rate obtained by modified C–J analysis was high up to the critical strain of 37% and then greatly decreased with further strain. The electron backscatter diffraction (EBSD) observation showed that the deformation twinning rate is greatly decreased beyond about 34% strain, indicating that the reduced strain hardening rate at the large strain region is attributed to the deceleration of deformation twinning rate. The volume fraction of twinned region was increased with tensile strain due to the increase in the number of deformation twins not to the lateral growth of each deformation twin.
212 citations
TL;DR: In this paper, an experimental investigation of spatio-temporal characteristics of the Portevin-Le Châtelier (PLC) effect in steel with twinning induced plasticity (TWIP) is presented.
170 citations
Cites background from "Deformation and fracture behaviour ..."
...Microstructural changes during plastic deformation of high Mn TWIP steels involve twin formation (see Bayraktar et al. (2004) for images of intergranular twins in a high Mn austenitic steel) due to a low stacking fault energy (SFE), where 18 mJ/m2 < SFE < 50–80 mJ/m2 (Iker et al., 2007), and planar…...
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...…of numerous theoretical and experimental studies of steel deformation (Shi and Northwood, 1995; de Almeida et al., 1998; Jenkins and Smith, 1969; Basinski 1957; Ilola et al., 1999; Bayraktar et al., 2004; Serajzadeh, 2003; Hong et al., 2005; de Almeida and Emygdio, 1994; Cuddy and Leslie, 1972)....
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...Dynamic strain aging and the PLC effect have been the subjects of numerous theoretical and experimental studies of steel deformation (Shi and Northwood, 1995; de Almeida et al., 1998; Jenkins and Smith, 1969; Basinski 1957; Ilola et al., 1999; Bayraktar et al., 2004; Serajzadeh, 2003; Hong et al., 2005; de Almeida and Emygdio, 1994; Cuddy and Leslie, 1972)....
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References
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TL;DR: The algorithm can be used as a building block for solving other distributed graph problems, and can be slightly modified to run on a strongly-connected diagraph for generating the existent Euler trail or to report that no Euler trails exist.
13,828 citations
TL;DR: In this article, a single-phase austenitic condition was studied and the apparent activation energies for the appearance and disappearance of serrations were found to be 104 and 146 kJ/mol, respectively, for static strain aging between 300 and 400 °C.
Abstract: When Hadfield manganese steel in the single-phase austenitic condition was strained in tension, in the temperature range - 25 to 300 °C, it exhibited jerky (serrated) flow, a negative (inverse) strain-rate dependence of flow stress and high work hardening, characteristic of dynamic strain aging. The strain rate-temperature regime of jerky flow was determined and the apparent activation energies for the appearance and disappearance of serrations were found to be 104 kJ/mol and 146 kJ/mol, respectively. The high work hardening cannot be a result of mechanical twinning because at -50 °C numerous twins were produced, but the work hardening was low and no twins were formed above 225 °C even though work hardening was high. The work hardening decreased above 300 °C because of the cessation of dynamic strain aging and increased again above 400 °C because of precipitation of carbides. An apparent activation energy of 138 kJ/mol was measured for static strain aging between 300 and 400 °C, corresponding closely to the activation energies for the disapperance of serrations and for the volume diffusion of carbon in Hadfield steel. Evidence from the present study, together with the known effect of manganese on the activity of carbon in austenite and previous internal friction studies of high-manganese steels, lead to the conclusion that dynamic strain aging, brought about by the reorientation of carbon members of C-Mn couples in the cores of dislocations, is the principal cause of rapid work hardening in Hadfield steel.
433 citations
TL;DR: In this paper, a model was presented that predicts the orientation and stress direction effects on the critical stress for initiating twinning in Hadfield steel, incorporating the role of local pile-up stresses, stacking fault energy, the influence of applied stress on the separation of partial dislocations, and the increase in the friction stress due to a high solute concentration.
347 citations
TL;DR: The plastic flow behavior of Hadfield manganese steel in uniaxial tension and compression is shown to be greatly influenced by transformation plasticity phenomena as mentioned in this paper, consistent with a softening effect of twinning as a deformation mechanism and a hardening effect on the twinned microstructure.
Abstract: The plastic flow behavior of Hadfield manganese steel in uniaxial tension and compression is shown to be greatly influenced by transformation plasticity phenomena. Changes in the stress-strain (σ−e) curves with temperature correlate with the observed extent of deformation twinning, consistent with a softening effect of twinning as a deformation mechanism and a hardening effect of the twinned microstructure. The combined effects give upward curvature to the σ−e curve over extensive ranges of plastic strain. A higher strain hardening in compression compared with tension appears to be consistent with the observed texture development. The composition dependence of stacking fault energy computed using a thermodynamic model suggests that the Hadfield composition is optimum for a maximum rate of deformation twinning. Comparisons of the Hadfield steel with a Co-33Ni alloy exhibiting similar twinning kinetics, and an Fe-21Ni-lC alloy deforming by slip indicate no unusual strain hardening at low strains where deformation is controlled by slip, but an unusual amount of structural hardening associated with the twin formation in the Hadfield steel. A possible mechanism of anomalous twin hardening is discussed in terms of modified twinning behavior (pseudotwinning) in nonrandom solid solutions.
298 citations
TL;DR: In this article, a viscoplastic self-consistent approach was used to model the stress-strain responses of single and polycrystals of Hadfield steel and a unique hardening formulation was proposed in the constitutive model incorporating length scales associated with spacing between twin lamellae and grain boundaries.
264 citations