Transitions in the strain hardening behaviour of tempered martensite

Wang, Lingyu; Wu, Yuxiang; Sun, Weifeng; Bréchet, Y.; Brassart, Laurence; Arlazarov, Artem; Hutchinson, Christopher

doi:10.1016/j.actamat.2021.117397

Cited by 16 publications

(3 citation statements)

References 69 publications

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“…Similarly, the uniform elongation increases by increasing the strength level (and hence by carbon content), contrary to the more common trade-off between strength and ductility (i.e. the 'banana curve' showing strength versus ductility in steels) (Krauss, 2001;Hutchinson et al, 2018;Krauss, 1999;Allain et al, 2012;Wang et al, 2021).…”

Section: Introductionmentioning

confidence: 87%

“…This model assumes the anisotropic yielding of the packets to be due to substructure boundary sliding mechanism, which is modeled via a homogenized laminate of hard and thick layers of lath martensite with embedded thin and soft discrete planes of austenite. In our work, we do not address the narrowing of X-ray diffraction patterns observed in quenched martensitic steels, as it indeed can be due to either the relaxation of type II residual stresses (due to strains induced by the martensitic phase transformation), or the change in the initial dislocation density which is inherited from the martensitic transformation (Ungár et al, 2017;Hutchinson et al, 2018;Ódor et al, 2020;Wang et al, 2021). Moreover, the observed strong Bauschinger effect is not studied here, since there is a lack of experimental information on the substructure boundary sliding phenomenon under non-monotonic loading conditions.…”

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confidence: 99%

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Influence of orientation-dependent lath martensite yielding on the hardening behavior of quenched martensitic steels

Rezazadeh¹,

Peerlings²,

Hoefnagels³

et al. 2022

Preprint

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The onset of plasticity in quenched martensitic microstructures is characterized by a low initial yield stress followed by an extremely strong initial hardening response, and then a sudden hardening saturation. Literature attributes this behavior to residual stresses and dislocations inherited from the martensitic transformation, or to microstructural heterogeneities causing strength differences among the grains. Here, we argue that orientation-dependent yielding of lath martensite due to inter-lath sliding, which induces a substructure boundary sliding mechanism that may also contribute significantly to the observed behavior. To demonstrate this, we systematically study its quantitative contribution to the elasto-plastic transition behavior in a numerical microstructural model. In the simulations, we employ an effective laminate model for the martensite packets which takes into account the yielding anisotropy due to sliding along the packet's habit plane orientation. To account for the effect of carbon content, martensitic microstructures with different levels of lath strength are considered. It is shown that the martensite packets with a favorable habit plane orientation start to yield earlier compared to those with an unfavorable orientation, which initially remain elastic. As a consequence, the macro-scale response of the microstructures exhibits a low yield stress, followed by a significant degree of initial hardening which continues until the saturation stress level is approached. The apparent work hardening rate depends on the contrast between the in-habit plane and out-of-habit plane yield strength used in the model. Moreover, our simulations are able to qualitatively capture other observations reported in the literature regarding the high initial hardening behavior of quenched martensitic steels, e.g. that the initial plastic yielding is independent of carbon content and thus of lath strength, and that the uniform elongation increases by increasing the macroscopic strength.

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Section: Introductionmentioning

confidence: 87%

mentioning

confidence: 99%

Influence of orientation-dependent lath martensite yielding on the hardening behavior of quenched martensitic steels

Rezazadeh¹,

Peerlings²,

Hoefnagels³

et al. 2022

Preprint

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“…However, it is not sufficient to suppress bainitic transformation during the hot-dip galvanization process and is harmful to galvanization quality [14]. Even though it has been proven in several studies that this situation can be improved by adding the alloy Mo, the high cost is an unavoidable disadvantage [15][16][17]. According to previous studies, Cr has a similar effect to Mo, but the cost is significantly lower than Mo [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Effect of Chromium on Microstructure and Mechanical Properties of Hot-Dip Galvanized Dual-Phase (DP980) Steel

Chen,

Liang,

Yang

et al. 2023

Crystals

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Generally, the addition of Chromium (Cr) into the dual-phase (DP) steels can suppress bainitic transformation. In this work, the continuous hot-dip galvanization of DP980 steel is thermally simulated with various Cr contents of 0/0.3/0.6 wt.%, and the effect of Cr on bainitic transformation and properties of steels is studied. The results indicate that the bainitic transformation is obviously inhibited. The fraction of bainite decreases with the increasing Cr content. The incubation time is prolonged in the 0.6Cr steel with a slower bainitic transformation rate. Compared to that of 0 and 0.3Cr steels, the 0.6Cr steel exhibits a high tensile strength of 1033 MPa and uniform elongation of 9.1% due to the rapid strain-hardening rate. As a result, the mechanical properties of 0.6Cr steel satisfy the requirements of hot-dip galvanized DP980 steel.

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