Micromechanisms of deformation of an austenoferritic duplex stainless steel

Verhaeghe, Bénédicte; Louchet, F.; Doisneau-Cottignies, B.; Bréchet, Y.; Massoud, J.P.

doi:10.1080/01418619708200016

Cited by 29 publications

(12 citation statements)

References 16 publications

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“…It has also been reported [5] that at intermediate temperatures in the range 300-400 • C, an increase in the flow stress and a significant embrittlement has been noticed. This was attributed to the structure of the ferrite where Cr-rich and Fe-rich domains appear, often accompanied by the precipitation of a (Ni, Si and Mo)-rich G-phase.…”

Section: Introductionmentioning

confidence: 94%

Non-uniform distribution of plastic strain in duplex steel during TEM in situ deformation

Zieliński

Świątnicki

Barstch

et al. 2003

Materials Chemistry and Physics

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Transmission electron microscopy (TEM) in situ straining experiments were carried out on duplex ferritic-austenitic steel. Localization of strain as a common feature during slip transfer from the austenite to the ferrite has been noticed. The character of strain localization depends on the orientation relationship between the phases. A possible influence of the TEM specimen geometry on the mechanism of plastic deformation of the ferritic-austenitic steel was considered by comparing the results with those of in situ straining experiments have been performed in a 1 MV high-voltage TEM instrument.

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Section: Introductionmentioning

confidence: 94%

Non-uniform distribution of plastic strain in duplex steel during TEM in situ deformation

Zieliński

Świątnicki

Barstch

et al. 2003

Materials Chemistry and Physics

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“…The results are displayed in Table 3, from which the phase boundary appears a moderate coefficient (307.9 MPa μm ) [36,44]. During plastic deformation, the dislocation transmission across phase boundary could occur in DSS when the slip planes in austenite and ferrite are nearly parallel [45]. It is the possible Fig.…”

Section: Strengthening Mechanism Of Dual Phase Microstructurementioning

confidence: 99%

Simultaneous improvement of tensile strength and ductility in micro-duplex structure consisting of austenite and ferrite

Chen

Yuan

Jiang

et al. 2014

Materials Science and Engineering: A

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a b s t r a c tA micro-duplex structure consisting of austenite and ferrite was produced by equal channel angular pressing and subsequent intercritical annealing. As compared to coarse-grained (CG) counterpart, the strength and ductility of micro-duplex samples are enhanced simultaneously due to smaller grain sizes in both phases and more uniformly distributed austenite in ferrite matrix. The average yield stress and uniform elongation are increased to 540 MPa and 0.3 as compared to 403MPa and 0.26 of its CG counterpart respectively. The Hall-Petch coefficients of austenite and ferrite grain boundaries were quantitatively measured as 224.9 and 428.9 MPa μm 1/2 respectively. In addition, a Hall-Petch type coefficient was used to describe the ability of phase boundary to obstruct dislocation motion, which was measured as 309.7 MPa μm 1/2 . Furthermore, the surface-to-volume ratio of phase boundary in microduplex structure was estimated to be 1.17 Â 10 6 m À 1 , which is increased by an order of magnitude as compared to 1.2 Â 10 5 m À 1 of its CG counterpart. Based on the strain gradient theory, a model was proposed to describe the effect of surface-to-volume ratio of phase boundary on strain hardening rate, which shows a good agreement with the experimental results.

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“…This is consistent with the equilibrium FCC copper precipitates remaining shearable to large sizes, facilitated by the Kurdjumov-Sachs orientation relationship between the precipitates and matrix, which results in some common slip systems. 36) In summary, this precipitation hardening system displays two unusual phenomena in its plastic behavior: i) the peak strength is associated with a high work hardening rate and ii) the lowest level of work hardening rate occurs for long term overaged conditions. This has consequences on the evolution of ductility, as shown in Fig.…”

Section: Work Hardening Behaviormentioning

confidence: 99%

Precipitation Kinetics and Strengthening of a Fe-0.8wt%Cu Alloy.

2001

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Precipitation kinetics and strengthening have been investigated for a Fe-0.8wt%Cu alloy. Microstructure evolution during aging at 500°C has been studied by a combination of Transmission Electron Microscopy and Small-Angle X-ray Scattering to provide information on the nature and location of the precipitates as well as a quantitative estimate of their size and volume fraction. The associated mechanical properties have been studied by hardness and tensile tests.The precipitation kinetics measured in this study are fully compatible with results reported for alloys with higher Cu levels. Nucleation of Cu precipitates is promoted by the presence of dislocations whereas coarsening rates in the later stages of aging appear to be not affected by fast diffusion paths along dislocations.The strength of individual precipitates increases with precipitate size based on the analysis of the mechanical test results. However, the strength of the largest precipitates observed remains approximately half of the strength required for the Orowan by-passing mechanism. The Russell-Brown model for modulus strengthening has successfully been applied to the current data.Study of the plastic behavior shows that the maximum initial hardening rate is related to the highest strength of the material. This unusual result may be explained by a dynamic strained-induced phase transformation of the precipitates from the bcc to the 9R structure. Consequently, the hardening potential of Fe-Cu alloys is associated with good plastic properties close to peak strength thereby indicating the excellent potential of copper as hardening element for the development of novel high strength interstitial free (IF) steels.KEY WORDS: iron-copper alloy; precipitation kinetics; precipitation strengthening; strain hardening; smallangle X-ray Scattering.formation to the 9R structure has been initiated. 10,11,19) The strengthening is usually described by employing the approach of Russell and Brown which is based on modulus strengthening. 20) This approach allows for the prediction of mechanical properties during an aging treatment assuming that the strength of the interaction between the dislocation and the precipitate increases with particle size. An alternative approach has recently been proposed by Osamura et al.,19) assuming that the hardening during the initial stage is controlled by coherency strains. The decrease in strength after the peak strength is attributed to the loss of coherency of the precipitates. Currently available experimental data do not allow to give preference to one of these two models.The effect of precipitation, coupled with the evolution of solid solution content, on the overall work hardening behavior is still poorly understood. Current knowledge derives from the pioneering contribution of Hornbogen et al. 21) where a few curves of initial work hardening rates are presented. More generally, a limited theoretical framework including the effect of bypassed precipitates has been proposed recently by Estrin,22) but the complete picture is still ...

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Micromechanisms of deformation of an austenoferritic duplex stainless steel

Cited by 29 publications

References 16 publications

Non-uniform distribution of plastic strain in duplex steel during TEM in situ deformation

Non-uniform distribution of plastic strain in duplex steel during TEM in situ deformation

Simultaneous improvement of tensile strength and ductility in micro-duplex structure consisting of austenite and ferrite

Precipitation Kinetics and Strengthening of a Fe-0.8wt%Cu Alloy.

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