Speaker
Description
Understanding the relationship between microstructure and properties is a necessary step for the improvement of existing materials or the development of new materials. The microstructure can be characterised using orientations maps, from which information like grain size distribution and deformation state can be extracted.
Apart from EBSD (Electron Backscattered Diffraction), a promising approach to obtain orientation maps with the SEM (Scanning Electron Microscope) is the eCHORD method [1], which is based on electron channelling contrast. This method has the advantage that the sample tilt is only about 10°, and that the accelerating voltage can be lowered to a few kV, resulting in an improved spatial resolution. A series of BSE images is recorded during the rotation of the sample around its tilted normal direction, from which the intensity profiles of each pixel can be extracted as a function of the rotation angle. By comparing the obtained intensity profiles with the one calculated from ECP (Electron Channelling Patterns) simulations, the orientation of each pixel can be determined. The angular resolution achieved on Aluminium alloys is about 0.1°.
In addition to orientation maps, we present here an original method to characterize the local disorientation by comparing the distances between profiles of adjacent pixels, without the need to compute pixels orientation. The results are compared with EBSD Kernel maps obtained on Duplex steels with different levels of strain.
REF:
[1] C.Lafond, T.Douillard, S.Cazottes, P.Steyer, and C.Langlois. Electron CHanneling Orientation Determination (eCHORD): An original approach to crystalline orientation mapping. Ultramicroscopy,
186 :146–149, March 2018.
| Speaker Country | France |
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