Defining a relationship between pearlite morphology and ferrite crystallographic orientation

Durgaprasad, A.; Giri, Sushil; Lenka, S.; Kundu, Saurabh; Mishra, Sushil; Chandra, Sudeshna; Doherty, R.D.; Samajdar, I.

doi:10.1016/j.actamat.2017.02.008

Cited by 48 publications

(13 citation statements)

References 44 publications

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“…Therefore, while nanostructured pearlitic steel is of interest to the metallurgic community given its outstanding mechanical properties, especially when the interlamellae spacing is small (Masoumi et al, 2019), very few EBSD-based analyses have been conducted on this material and the information generated was always very limited. In SEM and on sub-200 nm cementite lamellae, analysis has been conducted so far either via EBSD pattern acquisition in spot mode with carefully selected incident beam positions (Takahashi et al, 2007; Zhang et al, 2007), via EBSD mapping of the ferritic matrix (Takahashi et al, 2007), or finally by cementite lamellae trace analysis (Guo & Liu, 2012; Durgaprasad et al, 2017). Figure 2 illustrates, on a small area containing 50 nm wide cementite lamellae, the difficulty to map cementite in pearlite by EBSD.…”

Section: Resultsmentioning

confidence: 99%

A Pattern Processing Method to Map Nanoscale Phases by EBSD

2022

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The crystallographic analysis of nanoscale phases with dimensions well below the spatial probing volume of electron backscatter diffraction (EBSD) traditionally rely on electron microscopy in transmission (either in SEM or TEM), because EBSD patterns are invariably dominated by the matrix phase contribution and present seemingly no trace from such nanoscale phases. Yet, this study shows that such nanoscale features generate a very faint but valuable secondary diffraction signal which can be retrieved. A diffraction pattern postprocessing method is presented which focuses on the detection of such secondary signal emitted by nanoscale minority phases in overlapped patterns dominated by a dominant matrix signal. The predominant, majority phase contribution in EBSD patterns is removed by a close-neighbor pattern subtraction routine, after which both the conventional Hough indexing method as well as pattern matching methods can be used to reveal the crystallography, spatial distribution, morphology, and orientation of nanoscale minority phases initially absent from EBSD maps. Nanolamellar pearlitic steel, which has long been out of reach for EBSD, has been chosen as an application example.

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Section: Resultsmentioning

confidence: 99%

A Pattern Processing Method to Map Nanoscale Phases by EBSD

2022

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“…The advantage of this method was that the difference in contrast under SEM can be used to qualitatively identify the grain misorientation. The EBSD samples were polished using GATAN Ilion II 697 argon ion polishing system, the voltage was 5 kV, and the polishing time was 2 h. The size of cementite was too thin to be resolved by EBSD system [17] , therefore, only the proeutectoid ferrite (Pro-F) and eutectoid ferrite (Eut-F) at different distances from surface were analyzed. The acceleration voltage was 20 kV, the working distance (WD) was 14 mm-16 mm, and the sample table tilt was 70°.…”

Section: Microstructure Characterizationmentioning

confidence: 99%

EBSD Study on Proeutectoid Ferrite and Eutectoid Ferrite Refinement Mechanism of D2 Wheel Steel Under a Rolling Condition

et al. 2021

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In this paper, the SEM (with EBSD system) is used to study the re nement mechanism of proeutectoid ferrite (Pro-f) and eutectoid ferrite (Eut-f) of D2 wheel steel in a rolling contact. The results indicate that with the increase of the shear strain (γ<0.21), the dislocation density in the proeutectoid ferrite increased continuously, and the dislocation cells formed were uniformly distributed in the grains. Subsequently, the dislocation cell boundaries were changed into low-angle boundaries (LABs), and then the low-angle boundaries were gradually changed into the high-angle boundaries (HABs), and the average grain size was re ned from the original 8 μm to 710 nm. When the shear strain is at 0.21≤γ≤0.84, dislocation piled up occurred at the ferrite side of the interface of eutectoid ferrite/cementite, and the spatial misorientation between adjacent two eutectoid ferrites increased gradually, then the ferrite lamellar is divided into bamboo-like by the low-angle boundaries, and proeutectoid ferrite the grains are gradually re ned into equiaxed grain. When the shear strain is at 0.84<γ<3.314, the number of high-angle boundaries inside the eutectoid ferrite lamellar increased, and it is re ned into bamboo-like grains. The two kinds of ferrite grains are repeatedly re ned many times by the equiaxial grains "elongation-bamboo like re nement-elongation", which gradually reduced the size difference. As the shear strain further increases, the two kinds of ferrite are completely mixed into the same morphology, the dislocation density is dramatically reduced, and ultra-ne equiaxed grains about 110 nm is formed.

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“…[ 38 ] So it will be an important task to explain the transformation process of flaky pearlite, in other words, the growth process of pearlite in 3D space. Moreover, the electron backscattered diffraction (EBSD) technique always obtained a large analysis area, which was the reason why it was possibly only suitable for the analysis of coarse grain, [ 39 ] but not of interface structure. Hence, the purpose of this article is to observe and analyze the microstructure of intragranular pearlite in 100Mn13 high‐carbon, high‐manganese steel aged at 600 °C using SEM and TEM, and provide the updated growth models describing the morphology and growth process in 3D space.…”

Section: Introductionmentioning

confidence: 99%

3D Growth of Intragranular Pearlite in an Aged 100Mn13 Steel

Liang

Ding

et al. 2021

steel research int.

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The morphology and microstructure of intragranular pearlite in 100Mn13 high‐carbon, high‐manganese steel aged at 600 °C are observed by a scanning electron microscope (SEM) and transmission electron microscope (TEM) and analyzed, and growth models describing the morphology and growth process in 3D space are proposed. The results show that pearlite could nucleate directly in the austenite grain and present a 3D morphology after deep etching, and ferrite and cementite in pearlite keep the orientation relationship (OR) with austenite, ( 2 2 false¯ 0 ) γ // ( 10 4 false¯ ) M 3 C , ( 1 false¯ 1 1 false¯ ) γ // ( 01 1 false¯ ) α , ( 0 1 false¯ 1 false¯ ) α // ( 1 false¯ 1 2 false¯ ) M 3 C , and [ 110 ] γ // [ 100 ] α // [ 461 ] M 3 C . Also, the overall continuous ledges at the lamellar ferrite surface and end surround the whole ferrite lamellae, corresponding to a fringe structure and a curved frontier interface in 2D space, which shows a terraced morphology in 3D space. The different structures of the α/γ interface in 3D directions result in different growth rates of ferrite lamellae, that is, edgewise grows fastest along the direction of [ 01 1 false¯ ] α due to the incoherent interface composed of ( 0 1 false¯ 1 false¯ ) α / / ( 1 2 false¯ 1 false¯ ) γ with a 28% mismatch, and sidewise grows slowest along the direction of [ 0 1 false¯ 1 false¯ ] α due to the coherent interface composed of ( 01 1 false¯ ) α / / ( 1 1 false¯ 1 ) γ with a 1.9% mismatch.

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Defining a relationship between pearlite morphology and ferrite crystallographic orientation

Cited by 48 publications

References 44 publications

A Pattern Processing Method to Map Nanoscale Phases by EBSD

A Pattern Processing Method to Map Nanoscale Phases by EBSD

EBSD Study on Proeutectoid Ferrite and Eutectoid Ferrite Refinement Mechanism of D2 Wheel Steel Under a Rolling Condition

3D Growth of Intragranular Pearlite in an Aged 100Mn13 Steel

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