Temperature-Dependent Mechanical Stability of Retained Austenite in Thermomechanically Processed 3Mn Steel

2021 ◽  
Vol 1016 ◽  
pp. 762-767
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański
Keyword(s):  
Retained Austenite ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Trip Effect ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Static Tensile ◽  
The Stability ◽  
Backscatter Diffraction

The temperature-dependent mechanical stability of retained austenite in medium-Mn transformation induced plasticity 0.17C-3.3Mn-1.6Al-1.7Al-0.22Si-0.23Mo thermomechanically processed steel was investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) methods. Specimens were deformed up to rupture in static tensile tests in a temperature range 20–200°C. It was found that deformation temperature affects significantly the intensity of TRIP effect. In case of specimens deformed at temperatures higher than 60°C, a gradual temperature-related decrease in the stability of γ phase was noted. It indicates a progressive decrease of the significance of the TRIP effect and at the same time the growing importance of the thermally activated processes affecting a thermal stability of retained austenite.

scholarly journals Microstructure Evolution and Mechanical Stability of Retained Austenite in Medium-Mn Steel Deformed at Different Temperatures

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3042 ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Adam Grajcar
Keyword(s):  
Microstructure Evolution ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Thermomechanical Processing ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Medium Mn Steel ◽  
Different Temperatures ◽  
Static Tensile ◽  
Xrd Techniques

The temperature-dependent microstructure evolution and corresponding mechanical stability of retained austenite in medium-Mn transformation induced plasticity (TRIP) 0.17C-3.1Mn-1.6Al type steel obtained by thermomechanical processing was investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) techniques. Specimens were deformed up to rupture in static tensile tests in the temperature range 20–200 °C. It was found that an increase in deformation temperature resulted in the reduced intensity of TRIP effect due to the higher stability of retained austenite. The kinetics of strain-induced martensitic transformation was affected by the carbon content of retained austenite (RA), its morphology, and localization in the microstructure.

scholarly journals Microstructure–Property Relationships in Thermomechanically Processed Medium-Mn Steels with High Al Content

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 929 ◽  
Author(s):  
Adam Grajcar ◽  
Andrzej Kilarski ◽  
Aleksandra Kozlowska
Keyword(s):  
Mechanical Properties ◽  
Martensitic Transformation ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Manganese Content ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Al Content ◽  
Static Tensile ◽  
High Al Content

Detailed studies on microstructure–property relationships of thermomechanically processed medium-Mn steels with various manganese contents were carried out. Microscopic techniques of different resolution (LM, SEM, TEM) and X-Ray diffraction methods were applied. Static tensile tests were performed to characterize mechanical properties of the investigated steels and to determine the tendency of retained austenite to strain-induced martensitic transformation. Obtained results allowed to characterize the microstructural aspects of strain-induced martensitic transformation and its effect on the mechanical properties. It was found that the mechanical stability of retained austenite depends significantly on the manganese content. An increase in manganese content from 3.3% to 4.7% has a significant impact on the microstructure, stability of γ phase and mechanical properties of the investigated steels. The initial amount of retained austenite was higher for the 3Mn-1.5Al steel in comparison to 5Mn-1.5%Al steel—17% and 11%, respectively. The mechanical stability of retained austenite is significantly affected by the morphology of this phase.

scholarly journals Mechanical and thermal stability of retained austenite in plastically deformed bainite-based TRIP-aided medium-Mn steels

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Ulrich Krupp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Cost Effective ◽  
Tensile Tests ◽  
Thermal Stability Of

AbstractAdvanced medium-Mn sheet steels show an opportunity for the development of cost-effective and light-weight automotive parts with improved safety and optimized environmental performance. These steels utilize the strain-induced martensitic transformation of metastable retained austenite to improve the strength–ductility balance. The improvement of mechanical performance is related to the tailored thermal and mechanical stabilities of retained austenite. The mechanical stability of retained austenite was estimated in static tensile tests over a wide temperature range from 20 °C to 200 °C. The thermal stability of retained austenite during heating at elevated temperatures was assessed by means of dilatometry. The phase composition and microstructure evolution were investigated by means of scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and transmission electron microscopy techniques. It was shown that the retained austenite stability shows a pronounced temperature dependence and is also stimulated by the manganese addition in a 3–5% range.

Growth of 4H-SiC Single Crystals on 6H-SiC Seeds with an Open Backside by PVT Method

2009 ◽  
Vol 615-617 ◽  
pp. 15-18 ◽  
Author(s):  
Emil Tymicki ◽  
Krzysztof Grasza ◽  
Katarzyna Racka ◽  
Marcin Raczkiewicz ◽  
Tadeusz Łukasiewicz ◽  
...  
Keyword(s):  
Single Crystals ◽  
Electron Backscatter Diffraction ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Optical Scanning ◽  
Atomic Force ◽  
The Stability ◽  
Backscatter Diffraction ◽  
Source Materials

4H-SiC single crystals grown by the seeded physical vapour transport method have been investigated. These crystals were grown on 6H-SiC seeds. The influence of the seed temperature, form and granulation of SiC source materials on the stability and efficiency of the 4H polytype growth have been investigated. A new way of the seed mounting - with an open backside - has been used. Crystals obtained were free of structural defects in the form of hexagonal voids. The crystalline structure of SiC crystals was investigated by EBSD (Electron Backscatter Diffraction) and X-Ray diffraction methods. Moreover, defects in crystals and wafers cut from these crystals were examined by optical, scanning electron and atomic force microscopy combined with KOH etching.

scholarly journals Microstructural Features of Strain-Induced Martensitic Transformation in Medium-Mn Steels with Metastable Retained Austenite/ Cechy Mikrostrukturalne Indukowanej Odkształceniem Przemiany Martenzytycznej W Stalach Sredniomanganowych Z Metastabilnym Austenitem Szczątkowym

2014 ◽  
Vol 59 (4) ◽  
pp. 1673-1678 ◽  
Author(s):  
A. Grajcar ◽  
A. Kilarski ◽  
K. Radwanski ◽  
R. Swadzba
Keyword(s):  
Electron Microscopy ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Tensile Tests ◽  
Bainitic Steels ◽  
Transmission Electron ◽  
Strain Induced Martensite ◽  
Backscatter Diffraction

Abstract The work addresses relationships between the microstructure evolution and mechanical properties of two thermomechanically processed bainitic steels containing 3 and 5% Mn. The steels contain blocky-type and interlath metastable retained austenite embeded between laths of bainitic ferrite. To monitor the transformation behaviour of retained austenite into strain-induced martensite tensile tests were interrupted at 5%, 10%, and rupture strain. The identification of retained austenite and strain-induced martensite was carried out using light microscopy (LM), scanning electron microscopy (SEM) equipped with EBSD (Electron Backscatter Diffraction) and transmission electron microscopy (TEM). The amount of retained austenite was determined by XRD. It was found that the increase of Mn addition from 3 to 5% detrimentally decreases a volume fraction of retained austenite, its carbon content, and ductility.

scholarly journals Mechanical stability of retained austenite in aluminum-containing medium-Mn steel deformed at different temperatures

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Krzysztof Radwański ◽  
Krzysztof Matus ◽  
Ludovic Samek ◽  
Adam Grajcar
Keyword(s):  
Electron Microscopy ◽  
Martensitic Transformation ◽  
Deformation Temperature ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Sheet Steel ◽  
Tensile Tests ◽  
X Ray ◽  
Different Temperatures

AbstractThe thermal and mechanical stabilities of retained austenite in aluminum-containing medium-Mn 0.16C–4.7Mn–1.6Al–0.2Si sheet steel were investigated. The strain-induced martensitic transformation in Mn TRIP steel was studied at different temperatures. Static tensile tests were carried out at the temperature ranging from − 60 to 200 °C. The tests allowed to study the influence of the temperature on austenite-to-martensite transformation kinetics. The interrupted tensile tests and corresponding X-ray measurements of retained austenite amount were performed to determine the mechanical stability of retained austenite using the Sugimoto model. The microstructure changes were investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Observed results reflected the effects of deformation temperature on the mechanical stability of retained austenite and the corresponding response of this phase to martensitic transformation. It was found that an increase in the deformation temperature resulted in the reduced intensity of the TRIP effect due to the higher mechanical stability of retained austenite. At the highest deformation temperature (200 °C), the evidence of thermally activated processes affecting the mechanical behavior was identified.

The Effect of Texture on the Stability of Retained Austenite in Al-Alloyed TRIP Steels

2011 ◽  
Vol 1296 ◽  
Author(s):  
Kemal Davut ◽  
Stefan Zaefferer
Keyword(s):  
Retained Austenite ◽  
Electron Backscatter Diffraction ◽  
High Strength ◽  
Trip Steels ◽  
Tension And Compression ◽  
Stable Austenite ◽  
Ebsd Technique ◽  
Face Centered ◽  
The Stability ◽  
Backscatter Diffraction

ABSTRACTSteels with transformation induced plasticity (TRIP) offer an excellent combination of high strength and ductility. The transformation of meta-stable austenite into martensite during straining leads to strong local hardening and prevents early localization of strain. Therefore, the mechanical properties of TRIP steels, including the damage resistance depend to a significant extent on the stability of retained austenite. The aim of this study was to evaluate the effect of texture on the stability of retained austenite. In order to compare the changes in both tension and compression the steel was deformed by a micro 3-point-bending device. The texture development upon bending was followed by electron backscatter diffraction (EBSD) technique. Based on a simple analysis using the relation between face centered cube (FCC) and body centered cube (BCC) shear geometries theoretically expected changes of texture components due to deformation are proposed. Using the results of this analysis the observed changes of the austenite texture due to deformation could be distinguished from those due to transformation, by comparing the experimental results with the theoretically expected behavior. From this comparison, austenite grains with “Brass (B) {011} <211>” and “Goss (G) {110} <100>” texture components were found to transform into martensite much easier than differently oriented grains.

scholarly journals Effect of Deformation Temperature on the Mechanical Behavior and Stability of Retained Austenite in TRIP-Assisted Medium-C Multiphase Steel

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2433 ◽  
Author(s):  
Adam Skowronek ◽  
Adam Grajcar
Keyword(s):  
Deformation Temperature ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Thermomechanical Processing ◽  
Tensile Tests ◽  
Thin Layers ◽  
Second Phase ◽  
Temperature Range ◽  
Static Tensile ◽  
The Impact

The temperature-dependent microstructural evolution and corresponding mechanical stability of retained austenite in medium-C TRIP-assisted 0.43C-1.45Mn-0.98Si-1Al-0.033Nb-0.01Ti steel obtained by thermomechanical processing was investigated using static tensile tests and microstructural studies. The light microscopy, image analysis, XRD diffraction and the Jaoul–Crussard analysis were applied to reveal relationships between microstructure and mechanical properties. Specimens were deformed in the static tensile tests in a temperature range of −20–140 °C. It was found that an increase in deformation temperature resulted in the reduced intensity of the TRIP effect due to the higher stability of retained austenite. An increase in the retained austenite stability along with a smaller grain size and a change from its blocky morphology to thin layers was also indicated. The impact of strengthening mechanisms at different temperatures was analyzed. The best combination of strength and ductility was obtained in the samples deformed at 20 and 60 °C, which is associated with the moderate work hardening in this temperature range. The Jaoul–Crussard analysis showed much less strengthening during the second phase of deformation at 100 and 140 °C due to the high stability of retained austenite. The higher C content in the investigated TRIP steel resulted in substantial volume fractions of retained austenite stable after completing deformation.

Application of Electron Backscatter Diffraction Techniques to Quenched and Partitioned Steels

2011 ◽  
Vol 17 (3) ◽  
pp. 368-373 ◽  
Author(s):  
Grant Thomas ◽  
John Speer ◽  
David Matlock ◽  
Joseph Michael
Keyword(s):  
Retained Austenite ◽  
Electron Backscatter Diffraction ◽  
X Ray Diffraction ◽  
Hot Strip ◽  
Electron Backscatter ◽  
Diffraction Patterns ◽  
Thermal Simulations ◽  
Hot Rolled ◽  
Backscatter Diffraction ◽  
Very High

AbstractElectron backscatter diffraction (EBSD) techniques were used to characterize “hot-rolled” quenched and partitioned microstructures produced via Gleeble thermal simulations representing a hot-strip cooling practice for steel. In particular, EBSD was utilized to positively identify the morphology and location of retained austenite, to qualitatively distinguish martensite from ferrite, and in an attempt to identify transition carbides. Large pools of retained austenite and some thin films were accurately indexed; however, there was some disparity between austenite volume fractions measured by EBSD and those measured by X-ray diffraction. Due to similarities between the crystal structures of martensite and ferrite (body centered tetragonal versus body centered cubic, respectively), martensite could not be distinguished from ferrite by indexing of diffraction patterns; however, martensite could qualitatively be distinguished from ferrite by regions of low image quality based on the very high dislocation density of martensite.

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