A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy

Gazder, Azdiar A.; Al-Harbi, Fayez; Spanke, Hendrik T.; Mitchell, David R. G.; Pereloma, Elena V.

doi:10.1016/j.ultramic.2014.07.005

Cited by 36 publications

(16 citation statements)

References 58 publications

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“…Based on this, the smaller second phase region contained more RA, however, it should be noted that only RA larger than 120 nm could be detected by EBSD due to the step size of 40 nm used. The sensitivity of EDS/EBSD simultaneous approach to carbon was proved by correlative electron microscopy study on TRIP steel [40]. As could be clearly seen in Fig.…”

Section: Ebsd and Apt Analysis Of The T 400 Samplementioning

confidence: 81%

“…11(a)). Bainitic ferrite is defined as ferrite laths separated by film RA and/or martensite; whereas, granular bainite is the arrangement of carbide-free bainite with irregular-shaped ferrite and dispersed blocky RA/martensite constituent [40]. Small second phase regions (3 -5 μm in equivalent circle diameter) transformed to bainitic ferrite or granular bainite during IBT holding (Fig.…”

Section: Scanning and Transmission Electron Microscopy Observationsmentioning

confidence: 99%

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Microstructures and mechanical properties of TRIP steel produced by strip casting simulated in the laboratory

Xiong

Kostryzhev

Saleh

et al. 2016

Materials Science and Engineering: A

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Conventional transformation induced plasticity (TRIP) steel (0.17C-1.52Si-1.61Mn-0.03Al, wt%) was produced via strip casting technology simulated in the laboratory. Effects of holding temperature, holding time and cooling rate on ferrite formation were studied via analysis of the continuous cooling transformation diagram obtained here. A typical microstructure for conventional TRIP steels consisting of ~ 0.55 fraction of polygonal ferrite with bainite, retained austenite and martensite was obtained. However, coarse prior austenite grain size of ~80 μm led to large polygonal ferrite grain size of ~17 μm, coarse second phase regions of ~21 μm size, small amount of retained austenite (0.02-0.045) and the presence of Widmanstätten ferrite. Optimisation of the microstructure-property relationship was reached via a variation in the isothermal bainite transformation temperature. The highest retained austenite fraction of 0.045±0.003 with medium carbon content of 1.23±0.01 wt% was obtained after holding at 400 °C, resulting in the highest ultimate tensile strength of 590±35 MPa and largest total elongation of 0.27±0.05. The presence of TRIP effect in the studied steel was revealed through the analysis of strain hardening exponent and modified Crussard-Jaoul model. Effect of processing parameters on retained austenite retention and stress-strain behaviour was discussed. Conventional transformation induced plasticity (TRIP) steel (0.17C-1.52Si-1.61Mn-0.03Al, wt. %) was produced via strip casting technology simulated in the laboratory. Effects of holding temperature, holding time and cooling rate on ferrite formation were studied via analysis of the continuous cooling transformation diagram obtained here. A typical microstructure for conventional TRIP steels consisting of ~ 0.55 fraction of polygonal ferrite with bainite, retained austenite and martensite was obtained. However, coarse prior austenite grain size of ~ 80 μm led to large polygonal ferrite grain size of ~ 17 μm, coarse second phase regions of ~ 21 μm size, small amount of retained austenite (0.02 -0.045) and the presence of Widmanstätten ferrite. Optimisation of the microstructure-property relationship was reached via a variation in the isothermal bainite transformation temperature. The highest retained austenite fraction of 0.045±0.003 with medium carbon content of 1.23±0.01 wt. % was obtained after holding at 400 °C, resulting in the highest ultimate tensile strength of 590±35 MPa and largest total elongation of 0.27±0.05. The presence of TRIP effect in the studied steel was revealed through the analysis of strain hardening exponent and modified Crussard -Jaoul model. Effect of processing parameters on retained austenite retention and stress-strain behaviour was discussed.

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Section: Ebsd and Apt Analysis Of The T 400 Samplementioning

confidence: 81%

Section: Scanning and Transmission Electron Microscopy Observationsmentioning

confidence: 99%

Microstructures and mechanical properties of TRIP steel produced by strip casting simulated in the laboratory

Xiong

Kostryzhev

Saleh

et al. 2016

Materials Science and Engineering: A

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show abstract

“…4). Bainitic ferrite consists of ferrite laths separated by film RA; whereas, granular bainite includes irregularshaped ferrite with dispersed blocky martensite and/or retained austenite (M/RA) constituent [36,37]. With an increase in IBT temperature to 400 °C (TD 400), the phase balance in the TRIP steel was similar to that in the TD 350 sample, as shown in Fig.…”

Section: Effect Of Isothermal Bainite Transformation Temperature On Mmentioning

confidence: 84%

Microstructure and mechanical properties of strip cast TRIP steel subjected to thermo-mechanical simulation

Xiong

Kostryzhev

Liang

et al. 2016

Materials Science and Engineering: A

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Instead of hot rolling and cold rolling followed by annealing, strip casting is a more economic and environmentally friendly way to produce transformation-induced plasticity (TRIP) steels. According to industrial practice of strip casting, rapid cooling in this work was achieved using a dip tester, and a Gleeble 3500 thermo-mechanical simulator was used to carry out the processing route. A typical microstructure of TRIP steels, which included ~0.55 fraction of polygonal ferrite with bainite, retained austenite and martensite, was obtained. The effects of deformation (0.41 reduction) above non-recrystallisation temperature, isothermal bainite transformation temperature and the size of second phase region on microstructure and mechanical properties were studied. The steel isothermally transformed at 400 °C had the best combination of ultimate tensile strength (UTS) and total elongation (TE), whether deformation was applied or not. The deformation resulted in the improvement of mechanical properties after holding at 400 °C: the UTS increased from 590 to 696 MPa and TE decreased from 0.27 only to 0.26. It was predominantly ascribed to grain size refinement and dislocation strengthening. The studied TRIP steel had comparable mechanical properties with TRIP 690 produced commercially. Abstract: Instead of hot rolling and cold rolling followed by annealing, strip casting is a more economic and environmentally friendly way to produce transformation-induced plasticity (TRIP) steels. According to industrial practice of strip casting, rapid cooling in this work was achieved using a dip tester, and a Gleeble 3500 thermo-mechanical simulator was used to carry out the processing route. A typical microstructure of TRIP steels, which included ~ 0.55 fraction of polygonal ferrite with bainite, retained austenite and martensite, was obtained. The effects of deformation (0.41 reduction) above non-recrystallisation temperature, isothermal bainite transformation temperature and the size of second phase region on microstructure and mechanical properties were studied. The steel isothermally transformed at 400 °C had the best combination of ultimate tensile strength (UTS) and total elongation (TE), whether deformation was applied or not. The deformation resulted in the improvement of mechanical properties after holding at 400 °C: the UTS increased from 590 to 696 MPa and TE decreased from 0.27 only to 0.26. It was predominantly ascribed to grain size refinement and dislocation strengthening. The studied TRIP steel had comparable mechanical properties with TRIP 690 produced commercially.

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“…The orientation relationship determined by EBSD can be more accurate than that determined by selected‐area diffraction of TEM. Combination of EDS and EBSD improves the quality of phase identification (Gazder et al ., ).…”

Section: What Sem Functions Are Needed To Understand Bulk Inorganic Mmentioning

confidence: 97%

Information or resolution: Which is required from an SEM to study bulk inorganic materials?

Xing

2016

Scanning

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Significant technological advances in scanning electron microscopy (SEM) have been achieved over the past years. Different SEMs can have significant differences in functionality and performance. This work presents the perspectives on selecting an SEM for research on bulk inorganic materials. Understanding materials demands quantitative composition and orientation information, and informative and interpretable images that reveal subtle differences in chemistry, orientation/structure, topography, and electronic structure. The capability to yield informative and interpretable images with high signal-to-noise ratios and spatial resolutions is an overall result of the SEM system as a whole, from the electron optical column to the detection system. The electron optical column determines probe performance. The roles of the detection system are to capture, filter or discriminate, and convert signal electrons to imaging information. The capability to control practical operating parameters including electron probe size and current, acceleration voltage or landing voltage, working distance, detector selection, and signal filtration is inherently determined by the SEM itself. As a platform for various accessories, e.g. an energy-dispersive spectrometer and an electron backscatter diffraction detector, the properties of the electron optical column, specimen chamber, and stage greatly affect the performance of accessories. Ease-of-use and ease-of-maintenance are of practical importance. It is practically important to select appropriate test specimens, design suitable imaging conditions, and analyze the specimen chamber geometry and dimensions to assess the overall functionality and performance of an SEM. For an SEM that is controlled/operated with a computer, the stable software and user-friendly interface significantly improve the usability of the SEM. SCANNING 38:864-879, 2016. © 2016 Wiley Periodicals, Inc.

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A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy

Cited by 36 publications

References 58 publications

Microstructures and mechanical properties of TRIP steel produced by strip casting simulated in the laboratory

Microstructures and mechanical properties of TRIP steel produced by strip casting simulated in the laboratory

Microstructure and mechanical properties of strip cast TRIP steel subjected to thermo-mechanical simulation

Information or resolution: Which is required from an SEM to study bulk inorganic materials?

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