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.

Microstructural Characterization of Hydrogen Induced Cracking in TRIP Steels by EBSD

2014 ◽  
Vol 922 ◽  
pp. 412-417 ◽  
Author(s):  
A. Laureys ◽  
Tom Depover ◽  
Roumen H. Petrov ◽  
Kim Verbeken
Keyword(s):  
Retained Austenite ◽  
Electron Backscatter Diffraction ◽  
Mechanical Load ◽  
High Strength ◽  
Microstructural Characterization ◽  
Trip Steels ◽  
Multiphase Microstructure ◽  
Hydrogen Induced Cracking ◽  
Backscatter Diffraction

The present work evaluates hydrogen induced cracking in a high strength TRIP steel with a complex multiphase microstructure, containing ferrite, bainite, retained austenite, and some martensite. Each structural constituent demonstrates a different behavior in the presence of hydrogen and when deformed, the retained austenite transforms to martensite. The goal of this work is to understand the response of the hydrogen saturated multiphase structure to a mechanical load. A tensile test on notched samples combined with in-situ electrochemical hydrogen charging was carried out. The test was interrupted at certain specific points, before the macroscopic failure of the material. Hydrogen induced crack initiation and propagation were examined by studying several intermediate elongations. The microstructure of the samples was characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The EBSD measurements allowed both microstructural and crystallographic characterization of the hydrogen induced crack surroundings. A correlation was found between the occurrence of martensite, which is known to be very susceptible to hydrogen embrittlement, and the initiation of hydrogen induced cracks. These cracks were located at the surface in specific high stressed regions. Finite element simulations indicated that these regions were induced due to the presence of the notch.

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.

Investigation of the Deformation Twins on the Bending Cross Section of TA2 Titanium Sheet

2020 ◽  
Vol 837 ◽  
pp. 41-45
Author(s):  
Shuai Sun ◽  
Kai Hua Liu
Keyword(s):  
Electron Backscatter Diffraction ◽  
Testing Machine ◽  
Pure Titanium ◽  
Titanium Sheet ◽  
Bending Tests ◽  
Three Point Bending ◽  
Deformation Twins ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
Deformation Area

In order to determine the evolution features of deformation twins for TA2 commercial pure titanium (cp-TA2), the TA2 samples were bent under different bending angles in three-point bending tests via a universal testing machine. The electron backscatter diffraction (EBSD) technique was applied to identify the grain boundaries (GBs) and twin boundaries (TBs) in the bending areas. The results reveal that the type of deformation area would effect the evolution of different deformation twins. It is inferred that the state of stress would promote the multiplication of the same type of deformation twins.

scholarly journals On the Use of EBSD and Microhardness to Study the Microstructure Properties of Tungsten Samples Prepared by Selective Laser Melting

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1215
Author(s):  
Mirza Atif Abbas ◽  
Yan Anru ◽  
Zhi Yong Wang
Keyword(s):  
Selective Laser Melting ◽  
Electron Backscatter Diffraction ◽  
Fusion Reactors ◽  
Laser Melting ◽  
Kikuchi Pattern ◽  
Plasma Facing Components ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Temperature Exposure ◽  
Backscatter Diffraction

Additively manufactured tungsten and its alloys have been widely used for plasma facing components (PFCs) in future nuclear fusion reactors. Under the fusion process, PFCs experience a high-temperature exposure, which will ultimately affect the microstructural features, keeping in mind the importance of microstructures. In this study, microhardness and electron backscatter diffraction (EBSD) techniques were used to study the specimens. Vickers hardness method was used to study tungsten under different parameters. EBSD technique was used to study the microstructure and Kikuchi pattern of samples under different orientations. We mainly focused on selective laser melting (SLM) parameters and the effects of these parameters on the results of different techniques used to study the behavior of samples.

Texture and Microstructure Evolution in Friction Stir Welded Cu-Al Sheets Characterized by EBSD

2011 ◽  
Vol 702-703 ◽  
pp. 574-577 ◽  
Author(s):  
Daniel Goran ◽  
G. Ji ◽  
M. N. Avettand-Fènoël ◽  
R. Taillard
Keyword(s):  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Weld Interface ◽  
Friction Stir ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Texture and microstructure of FSW joined Al and Cu sheets were investigated by means of electron backscatter diffraction (EBSD) technique. The analysis has revealed a strong texture evolution on both sides of the weld interface as well as a very complex microstructure. Grains were found to be fully recrystallized on both sides of the weld and with different average diameters at different specific zones of the weld.

scholarly journals Initiation and short crack growth behaviour of environmentally induced cracks in AA5083 H131 investigated across time and length scales

2019 ◽  
Vol 37 (5) ◽  
pp. 469-481 ◽  
Author(s):  
Visweswara C. Gudla ◽  
Alistair Garner ◽  
Malte Storm ◽  
Parmesh Gajjar ◽  
James Carr ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Three Dimensional ◽  
High Strength ◽  
Time Lapse ◽  
Growth Behaviour ◽  
Spectroscopy Analysis ◽  
Crack Growth Behaviour ◽  
Rate Testing ◽  
X Ray Computed ◽  
Backscatter Diffraction

AbstractEnvironmentally induced cracking (EIC) in a sensitized high-strength AA5083 H131 alloy has been investigated using time-lapse synchrotron X-ray computed tomography combined with post-mortem correlative characterization. Small corrosion features deliberately introduced in a pre-exposure step were found to be the site of initiation for over 95% of the 44 EIC cracks that developed under slow strain rate testing. Detailed analysis using three-dimensional electron backscatter diffraction and energy-dispersive spectroscopy analysis of a single crack confirmed the intergranular nature of the cracks from the start and that the pre-exposure corrosion was associated with an α-AlFeMnSi particle cluster. It also appears that several cracks may have initiated at this site, which later coalesced to form the 300-μm-long crack that ultimately developed. Of further note is the fact that initiation of the EIC cracks across the sample started below the yield strength and continued beyond the ultimate tensile strength. The most rapid crack propagation occurred during sample extension following a period of fixed displacement.

scholarly journals Application of Electron Backscatter Diffraction (EBSD) for Crystallographic Characterization of Aluminum-Doped Zinc Oxide Sputtered Films

2013 ◽  
Vol 19 (S4) ◽  
pp. 103-104
Author(s):  
C.B. Garcia ◽  
E. Ariza ◽  
C.J. Tavares
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Zinc Oxide ◽  
Electron Backscatter Diffraction ◽  
Wide Range ◽  
Electron Backscatter ◽  
Aluminum Doped Zinc Oxide ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Zinc Oxide is a wide band-gap compound semiconductor that has been used in optoelectronic and photovoltaic applications due to its good electrical and optical properties. Aluminium has been an efficient n-type dopant for ZnO to produce low resistivity films and high transparency to visible light. In addition, the improvement of these properties also depends on the morphology, crystalline structure and deposition parameters. In this work, ZnO:Al films were produced by d.c. pulsed magnetron sputtering deposition from a ZnO ceramic target (2.0 wt% Al2O3) on glass substrates, at a temperature of 250 ºC.The crystallographic orientation of aluminum doped zinc oxide (ZnO:Al) thin films has been studied by Electron Backscatter Diffraction (EBSD) technique. EBSD coupled with Scanning Electron Microscopy (SEM) is a powerful tool for the microstructural and crystallographic characterization of a wide range of materials.The investigation by EBSD technique of such films presents some challenges since this analysis requires a flat and smooth surface. This is a necessary condition to avoid any shadow effects during the experiments performed with high tilting conditions (70º). This is also essential to ensure a good control of the three dimensional projection of the crystalline axes on the geometrical references related to the sample.Crystalline texture is described by the inverse pole figure (IPF) maps (Figure 1). Through EBSD analysis it was observed that the external surface of the film presents a strong texture on the basal plane orientation (grains highlighted in red colour). Furthermore it was possible to verify that the grain size strongly depends on the deposition time (Figure 1 (a) and (b)). The electrical and optical film properties improve with increasing of the grain size, which can be mainly, attributed to the decrease in scattering grain boundaries which leads to an increasing in carrier mobility (Figure 2).The authors kindly acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) scientific program for the National Network of Electron Microscopy (RNME) EDE/1511/RME/2005.

Twin and topotactic growth of β-eucryptite dendrites and their lattice coincidence analysed by the reticular theory

2013 ◽  
Vol 46 (1) ◽  
pp. 216-223
Author(s):  
Shan-Rong Zhao ◽  
Hai-Jun Xu ◽  
Rong Liu ◽  
Qin-Yan Wang ◽  
Xian-Yu Liu
Keyword(s):  
Solid Solution ◽  
Crystallographic Orientation ◽  
Electron Backscatter Diffraction ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
Orientation Determination

Snowflake-shaped dendrites of β-eucryptite–β-quartz solid solution were artificially crystallized in a matt glaze, and the crystallographic orientation of the dendrites was analysed by the electron backscatter diffraction (EBSD) technique. The six branches of a snowflake-shaped dendrite in the plane (0001) are along 〈110〉. From the orientation determination, a twin relationship and a topotactic relationship between dendrites were found. The twin axes are [011], [0{\overline 1}1] and [210], and the twin planes perpendicular to the twin axes are ({\overline 1}2{\overline 1}2) and (1{\overline 2}12). From the reticular theory of twinning, it was calculated that the twin indexn= 2 and the obliquity ω = 3.2877°. The studied dendrite is a twin by reticular pseudomerohedry with low twin index and obliquity. In the topotactic growth, no twin elements have been found, but the three main crystallographic directions 〈001〉, 〈210〉 and 〈110〉 of the two dendritic crystals overlap each other. The degree of lattice coincidence between the two crystals in this topotactic growth is also discussed.

Influence of the Processing Variables on the Microstructure Evolution of a Bainitic Carbide-Free Steel

2016 ◽  
Vol 879 ◽  
pp. 867-872 ◽  
Author(s):  
M.C. Taboada ◽  
I. Gutiérrez ◽  
D. Jorge-Badiola ◽  
S.M.C. van Bohemen ◽  
F. Hisker ◽  
...  
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
High Volume ◽  
X Ray Diffraction ◽  
Tempered Martensite ◽  
Trip Steels ◽  
Volume Fractions ◽  
Advanced High Strength Steels ◽  
Processing Variables

New trends focused on achieving higher performance steels has led to a so-called 3rd Generation Advanced High Strength Steels (AHSS), in which the typical polygonal ferrite found in TRIP steels as a matrix phase is replaced by harder phases as Carbide-Free Bainite (CFB) and/or (tempered) martensite. Besides, large volume fractions of retained austenite (R.A.) with adequate stability are aimed for to improve the formability of the steels. Si containing steels are regarded as the most suitable to retard cementite formation and consequently reach high volume fractions of RA. In this work, CFB annealing schedules were applied to dilatometer samples of Fe-0.22C-2.0Mn-1.3Si. The overaging temperature TB was varied between 390 oC and 480 oC, and other processing variables investigated were the austenitizing temperature Taus, and the overaging holding time tB. The annealed samples analyzed with LOM, FEG-SEM, EBSD and X-ray diffraction techniques show that markedly different complex microstructures made up of bainite, ferrite, MA phase and retained austenite (R.A) are accomplished depending on the specific thermal cycle. These results are described in detail and discussed in relation to the dilatometry measurements.

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