scholarly journals Investigation of the α−γ−α Phase Transformation in Steel: High-Temperature In Situ EBSD Measurements

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
I. Lischewski ◽  
D. M. Kirch ◽  
A. Ziemons ◽  
G. Gottstein

A newly developed laser powered heating stage for commercial SEMs in combination with automated established electron backscatter diffraction (EBSD) data acquisition is presented. This novel experimental setup can be used to achieve more information about microstructure and orientation changes during grain growth, recrystallization, recovery, and phase transformations. First results on the α−γ−α phase transformation in steel within 886∘C–900∘C are presented.

2007 ◽  
Vol 561-565 ◽  
pp. 2087-2090 ◽  
Author(s):  
Ya Ming Huang ◽  
Qiang Fu ◽  
Chun Xu Pan

Electron backscatter diffraction (EBSD) has been developed as a novel technique for characterizing crystallographic textures in recent years. The present paper proposes an “in-situ-tracking” approach using SEM and EBSD to examining the microstructural development and grain boundary variation of stainless steel during elevated 1200 °C service. The results revealed that in addition to the coarsened grains the fraction of low angle grain boundaries (LABG) became increased and flattened obviously during service. Comparing to the regular high temperature service (below 900 °C), the present “recovery and recrystallization” process was accelerated due to dislocation fastened movement and intensive interaction. However, the grain growth mechanism still meet the well-accepted dislocation model of subgrain combination.


2013 ◽  
Vol 46 (4) ◽  
pp. 1145-1150 ◽  
Author(s):  
Melanie Syha ◽  
Andreas Trenkle ◽  
Barbara Lödermann ◽  
Andreas Graff ◽  
Wolfgang Ludwig ◽  
...  

Microstructure reconstructions resulting from diffraction contrast tomography data of polycrystalline bulk strontium titanate were reinvestigated by means of electron backscatter diffraction (EBSD) characterization. Corresponding two-dimensional grain maps from the two characterization methods were aligned and compared, focusing on the spatial resolution at the internal interfaces. The compared grain boundary networks show a remarkably good agreement both morphologically and in crystallographic orientation. Deviations are critically assessed and discussed in the context of diffraction data reconstruction and EBSD data collection techniques.


2004 ◽  
Vol 467-470 ◽  
pp. 935-940 ◽  
Author(s):  
Sandra Piazolo ◽  
Vera G. Sursaeva ◽  
David J. Prior

First results from grain growth experiments in a columnar structured Al foil show several interesting features: (a) the grain size distribution remains heterogeneous even after up to 300 min. annealing and (b) the Von Neumann-Mullins relation is not always satisfied. To clarify the underlying reasons for these features, in-situ heating experiments within a Scanning Electron Microscope (SEM) were combined with detailed Electron Backscatter Diffraction (EBSD) analysis. These show that the movement of boundaries can be strongly heterogeneous. For example, the complete replacement of one grain by a neighbouring grain without significant change of the surrounding grain boundary topology is frequently seen. Experiments show that grain boundary energy and/or mobility are anisotropic both with respect to misorientation and orientation of grain boundary plane. Low energy and/or mobility boundaries are commonly low angle boundaries, twin boundaries and boundaries that form traces to a low index plane of at least one of the adjacent grains. As a consequence the Von Neumann-Mullins relation is not always satisfied.


Microscopy ◽  
2020 ◽  
Author(s):  
Kaneaki Tsuzazki ◽  
Motomichi Koyama ◽  
Ryosuke Sasaki ◽  
Keiichiro Nakafuji ◽  
Kazushi Oie ◽  
...  

Abstract Microstructural changes during the martensitic transformation from face-centred cubic (FCC) to body-centred cubic (BCC) in an Fe-31Ni alloy were observed by scanning electron microscopy (SEM) with a newly developed Peltier stage available at temperatures to  −75°C. Electron channelling contrast imaging (ECCI) was utilized for the in situ observation during cooling. Electron backscatter diffraction analysis at ambient temperature (20°C) after the transformation was performed for the crystallographic characterization. A uniform dislocation slip in the FCC matrix associated with the transformation was detected at −57°C. Gradual growth of a BCC martensite was recognized upon cooling from −57°C to −63°C.


2009 ◽  
Vol 15 (3) ◽  
pp. 197-203 ◽  
Author(s):  
Alberto Pérez-Huerta ◽  
Maggie Cusack

AbstractElectron backscatter diffraction (EBSD) is becoming a widely used technique to determine crystallographic orientation in biogenic carbonates. Despite this use, there is little information available on preparation for the analysis of biogenic carbonates. EBSD data are compared for biogenic aragonite and calcite in the common blue mussel, Mytilus edulis, using different types of resin and thicknesses of carbon coating. Results indicate that carbonate biomineral samples provide better EBSD results if they are embedded in resin, particularly epoxy resin. A uniform layer of carbon of 2.5 nm thickness provides sufficient conductivity for EBSD analyses of such insulators to avoid charging without masking the diffracted signal. Diffraction intensity decreases with carbon coating thickness of 5 nm or more. This study demonstrates the importance of optimizing sample preparation for EBSD analyses of insulators such as carbonate biominerals.


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