Microstructure and texture of a lightly deformed TRIP-assisted steel characterized by means of the EBSD technique

Petrov, Roumen; Kestens, Léo; Wasilkowska, Anna; Houbaert, Yván

doi:10.1016/j.msea.2006.10.023

Cited by 177 publications

(94 citation statements)

References 14 publications

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“…Therefore, several studies were carried out to reveal the deformation behavior of retained austenite in TRIP steels [7][8][9]. Experimental investigations showed that the austenite stability is affected by: (i) the constraining effect from the phases surrounding the retained austenite [10], (ii) the crystallographic orientation of grains with respect to the loading direction [11], (iii) the local carbon concentration in the austenite [12] and (iv) the grain volume of the retained austenite grains [14].…”

Section: Introductionmentioning

confidence: 99%

Deformation-induced austenite grain rotation and transformation in TRIP-assisted steel

et al. 2012

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Uniaxial straining experiments were performed on a rolled and annealed Si-alloyed TRIP (transformation-induced plasticity) steel sheet in order to assess the role of its microstructure on the mechanical stability of austenite grains with respect to martensitic transformation. The transformation behavior of individual metastable austenite grains was studied both at the surface and inside the bulk of the material using electron back-scattered diffraction (EBSD) and X-ray diffraction (XRD) by deforming the samples to different strain levels up to about 20%. A comparison of XRD-and EBSD-results revealed that the retained austenite grains at the surface have a stronger tendency to transform than the austenite grains in the bulk of the material.The deformation-induced changes of individual austenite grains before and after straining were monitored with EBSD. Three different types of austenite grains can be distinguished that have different transformation behaviors: austenite grains at the grain boundaries between ferrite grains, twinned austenite grains, and embedded austenite grains that are completely surrounded by a single ferrite grain. It was found that twinned austenite grains and the austenite grains present at the grain boundaries between larger ferrite grains typically transform first, i.e. are less stable, in contrast to austenite grains that are completely embedded in a larger ferrite grain. In the latter case, straining leads to rotations of the harder austenite grain within the softer ferrite matrix before the austenite transforms into martensite. The analysis suggests that austenite grain rotation behavior is also a significant contributing factor for enhancement of the ductility.

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Section: Introductionmentioning

confidence: 99%

Deformation-induced austenite grain rotation and transformation in TRIP-assisted steel

et al. 2012

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“…In conventional TRIP steels, EBSD is a very useful technique to separate the retained austenite FCC phase from the other BCC phases since FCC and BCC phases have clearly different Kikuchi diffraction pattern (Herrera et al, 2011;Petrov et al, 2007;Zaefferer et al, 2004). However, separation of iron BCC phases is relatively difficult because they have similar crystallographic structure.…”

Section: Introductionmentioning

confidence: 99%

“…Over the past decade, many studies have benefited from the various tools of EBSD to distinguish the bainite and martensite. One of them is image quality (IQ), the quality metrics of the acquired electron back-scattering Kikuchi pattern that are derived from Hough transformation (Petrov et al, 2007;Wilson & Spanos, 2001;Wu et al, 2005). IQ describes the intensity of the Hough peaks which is affected by elastically distorted lattices and density of crystalline defects or residual stresses (Humphreys, 2001).…”

Section: Introductionmentioning

confidence: 99%

A Correlative Approach for Identifying Complex Phases by Electron Backscatter Diffraction and Transmission Electron Microscopy

Seol

Jafari

et al. 2017

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A new method was introduced to distinguish the ferrite, bainite and martensite in transformation induced plasticity (TRIP) steel by using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). EBSD is a very powerful microstructure analysis technique at the length scales ranging from tens of nanometers to millimeters. How ever, iron BCC phases such as ferrite, bainite and martensite cannot be easily distinguished by EBSD due to their similar surface morphology and crystallographic structure. Among the various EBSD-based methodology, image quality (IQ) values, which present the perfection of a crystal lattice, was used to distinguish the iron BCC phases. IQ values are very useful tools to discern the iron BCC phases because of their different density of crystal defect and lattice distortion. However, there are still remaining problems that make the separation of bainite and martensite difficult. For instance, these phases have very similar IQ values in many cases, especially in deformed region; therefore, even though the IQ value was used, it has been difficult to distinguish the bainite and martensite. For more precise separation of bainite and martensite, IQ threshold values were determined by a correlative TEM analysis. By determining the threshold values, iron BCC phases were successfully separated.

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“…Recientemente, en estos aceros se han realizado investigaciones orientadas al desarrollo de las texturas durante los procesos de conformado termomecá-nico [1][2][3] , donde principalmente se ha estudiado la influencia de los parámetros de proceso, como porcentajes de reducción, tiempo entre pasadas de laminación, temperatura de tratamiento, entre otras, en las orientaciones resultantes. Jonas [4 y 5] , ha sugerido que existe una fuerte correlación entre las características de la austenita (energía de falla de apilamiento, componentes de texturas presentes) y las características de la ferrita obtenida.…”

Section: Introductionunclassified

Caracterización de aceros dual-phase obtenidos por laminación en caliente

Colás

Houbaert³

2011

REVMETAL

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ResumenSe tomaron muestras de acero al C-Mn-Si disponible en el mercado y mediante un proceso de laminación en caliente y bobinado, se obtuvo acero Dual Phase con microestructura y propiedades mecánicas dentro del rango teórico esperado de este material. El proceso termomecánico consistió en producir una fuerte reducción a temperaturas mayores a A r3 , mediante pasadas de laminación sucesivas, para posteriormente enfriar el acero durante aproximadamente 5 s, (a una velocidad de 20°C/s) en el rango de equilibrio α+γ. La temperatura A r3 , medida mediante calorimetría diferencial de barrido, fue de 890°C. A continuación se realizó un temple en el rango de temperaturas de bobinado (550-675°C), enfriando posteriormente las muestras de acuerdo a una curva pre establecida, que corresponde a la curva de enfriamiento real de una bobina. La caracterización microestructural de las muestras obtenidas, se realizó mediante microscopía óptica, microscopía electrónica de barrido y microscopía de fuerza atómica. Adicionalmente se realizó una medición de texturas mediante difracción de rayos X, para el estudio de las orientaciones resultantes, producto de la variación de la temperatura de término de laminación (TTL) y la temperatura de bobinado (TB), determinándose cómo afectan estas variables a las distintas componentes de texturas. Se complementó la información microestructural con los valores de los índices de anisotropía normal y planar, medidos de acuerdo a la norma ASTM E-517. Se correlacionaron las intensidades de las componentes de texturas encontradas con los valores de los índices de anisotropía, encontrándose que sólo es posible producir leves mejoras en el índice de anisotropía normal, a través de una combinación apropiada de las temperaturas de término de laminación y de bobinado. Palabras claveAceros; Dual-Phase; Laminado en caliente; Texturas; Embutición. Characterization of dual-phase steels obtained by hot-rolling AbstractSamples were obtained from C-Mn-Si steel available in the market. Through a hot rolling and coiling process, it was possible to obtain Dual-Phase steel with microstructural and mechanical properties in the theoretical range typical of this material. The thermomechanical process consisted of a strong reduction by multiples pass of hot rolling at temperatures above A r3 , controlled-cooling the sheets during 5 s (at a rate of 20°C/s in the equilibrium range α+γ. Temperature A r3 measured by differential scanning calorimetry was 890°C. Quenching was then carried out in the coiling temperatures range (500-675°C), cooling the samples in accordance to an established curve that corresponds to the actual cooling curve of a coil. The microstructural characterization of the samples obtained was carried out by optical microscopy, scanning electron microscopy and atomic force microscopy. Additionally, texture measurements were carried out by X-ray diffraction in order to study the resulting orientations due to the finishing rolling temperature and coiling temperature, determining the influence on these par...

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Microstructure and texture of a lightly deformed TRIP-assisted steel characterized by means of the EBSD technique

Cited by 177 publications

References 14 publications

Deformation-induced austenite grain rotation and transformation in TRIP-assisted steel

Deformation-induced austenite grain rotation and transformation in TRIP-assisted steel

A Correlative Approach for Identifying Complex Phases by Electron Backscatter Diffraction and Transmission Electron Microscopy

Caracterización de aceros dual-phase obtenidos por laminación en caliente

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