Evolution of transformation plasticity during bainitic transformation

Lambers, Hans-Gerd; Tschumak, S.; Maier, Hans Jürgen; Canadinç, D.

doi:10.3139/146.110558

Cited by 6 publications

(5 citation statements)

References 34 publications

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“…An acceleration of transformation at temperatures just above the martensite start temperature has been confirmed, even in the absence of an externally applied stress [6]. The influences of prior austenitization treatment and the state of applied stresses on the evolution of transformation plasticity strains during isothermal bainitic phase transformation and the resulting microstructures were examined and analysed [7]. The key finding is that, upon pre-straining, the amount of transformation plasticity strain under superimposed elastic stresses is dictated by both the prior austenite grain size and the (0.01 % offset) yield strength of the supercooled austenite.…”

Section: Introductionmentioning

confidence: 89%

Experimental Analysis of Steel Plasticity Parameters during Quenching

Bendikienė

Vitkevičienė

2012

KEM

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The paper presents the results of longitudinal investigations of transformation plasticity, kinetic plasticity, elastic-plastic strain and auto deformation of different grades of steel during quenching. A special device was used to evaluate transformation plasticity and determine the maximum normal bending stress, modulus of transformation plasticity for high alloyed and high corrosion resistance steel. Other targets of experiments were to determine relations between magnitude of normal bending stresses and plastic deformation of test pieces, to examine influence of hardening temperature on the transformation plasticity, to calculate modulus of transformation plasticity Etp. As a complimentary survey we study the mechanical behaviour of high chromium and medium chromium steels during quenching. Understanding phenomenon of steel behaviour during quenching it is possible to renovate and restore the details and components deformed during exploitation, for production of steels with high formability, and to predict properties of steel.

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Section: Introductionmentioning

confidence: 89%

Experimental Analysis of Steel Plasticity Parameters during Quenching

Bendikienė

Vitkevičienė

2012

KEM

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“…there are different changes in length associated to the bainitic transformation, depending on the observation axis. [17][18][19][20][21] This transformation plasticity is due to the preferential selection of variants promoted by the applied stress. [19][20][21][22][23][24][25] However, one question that has not been answered yet, to the best knowledge of the authors, is what the effect of stress on the resultant microstructure, in terms of bainitic ferrite plate thickness and fraction of bainitic ferrite formed, is.…”

Section: Tuning Bainitic Microstructures By Complex Thermo-mechanical...mentioning

confidence: 99%

“…5(n), 5(o) showed a fair parallelism among plates that suggests that strong variant selection phenomena took place, in good agreement with the previously shown dilatometry results and with other works in the literature. [17][18][19][20][21][22][23][24][25] Deeper crystallographic studies would be needed to confirm variant selection. XRD results included in Fig.…”

Section: Effect Of Deformation In the Elastic And Plasticmentioning

confidence: 99%

Tuning Bainitic Microstructures by Complex Thermo-mechanical Treatments under Constant Stress

Eres-Castellanos,

Perez-Aroca,

Carrero-Santos

et al. 2024

ISIJ Int.

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Ausforming processes are those thermomechanical treatments in which austenite is plastically deformed before either a martensitic or a bainitic transformation takes place. Although the deformation of an austenitized steel at intermediate temperatures has many benefits, it can also induce displacive transformations, sometimes unavoidably at the industrial level. Although the addition of a mechanical driving force, associated to the applied stress, has been shown to accelerate the bainitic transformations and promote transformation plasticity and variant selection, little information is found on the effect of stress on parameters such as bainitic ferrite plate thickness or volume percentage of retained austenite. Some works suggest that constant stresses can coarsen bainitic ferrite plates and increase the amount of transformed bainitic ferrite, although no systematic work has been conducted in this regard. This work aims to better understand the characteristics of bainitic microstructures formed during the application of stress or under constant stress and discuss the mechanisms affecting the bainitic transformations. Among the obtained results, it can be highlighted that, at temperatures below the bainite start temperature, bainitic ferrite plates formed during straining are more refined that isothermally formed plates at the same temperature, whereas constant stresses leads to an increased fraction of coarser bainitic ferrite plates, as compared to those microstructures obtained at the same temperature.

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“…The TP strains are attributed to different mechanisms in literature, and one of these is bainite variant selection due to the superimposed stress present during the phase transformation. 8,[16][17][18][19][20][21] The presence of variant selection during the austenite-to-bainite phase transformation can be evidenced by a direct comparison between the DIC and the EBSD results (see Figure 6). The area marked with a white rectangle in Figure 5 was scanned by EBSD.…”

Section: Bainitic Transformationmentioning

confidence: 99%

Digital image correlation at high temperatures for fatigue and phase transformation studies

Holzweißig

Kanagarajah

Maier

2013

The Journal of Strain Analysis for Engineering Design

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In this study, digital image correlation was used for two widely different cases to assess the potential and the limitations of the technique for applications at high temperatures. Specifically, digital image correlation was employed in hightemperature low-cycle fatigue experiments in a nickel-based superalloy and in phase transformation experiments conducted on bainitic steel in order to shed light on the microstructural processes. Depending on the type of experiments, the microstructure was characterized prior to the experiments (fatigue) or after the experiments (phase transformation). In the fatigue experiments, it was found that the features dominating damage evolution were the dendrites resulting from the solidification of the cast material. In the phase transformation experiments, variant selection is active when stresses are superimposed during the phase transformation process, which resulted in the evolution of transformation plasticity strains. Thereby, mainly the bainite variants oriented along the [101], [201] and [121] directions were observed to grow parallel to the loading axis, which in turn led to transformation plasticity strains. For validation of the digital image correlation data, average strains were calculated for the surface area probed and compared to strain values obtained by conventional extensometry. In all cases studied, the correlation was satisfactory, indicating that digital image correlation can provide for additional insight into processes active at the micro level.

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Evolution of transformation plasticity during bainitic transformation

Cited by 6 publications

References 34 publications

Experimental Analysis of Steel Plasticity Parameters during Quenching

Experimental Analysis of Steel Plasticity Parameters during Quenching

Tuning Bainitic Microstructures by Complex Thermo-mechanical Treatments under Constant Stress

Digital image correlation at high temperatures for fatigue and phase transformation studies

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