On-axis versus off-axis Transmission Kikuchi Diffraction technique: application to the characterisation of severe plastic deformation-induced ultrafine-grained microstructures.
A new configuration for Transmission Kikuchi Diffraction (TKD) in a scanning electron microscope is presented; called 'on-axis TKD'. Compared to the usual off-axis configuration, the scintillator is placed perpendicular to the incident beam under the electron-transparent sample, not in vertical position. In this way, the setup benefits from intense forward scattered electrons enabling short acquisition times. At equivalent diffraction pattern quality, the electron dose needed on the sample is estimated to be 20 times lower in comparison to the off-axis configuration. The technique is particularly suited to the characterisation of severe plastic deformation induced ultrafine grained microstructures. The evolution of the microstructure of an Al-Mg alloy deformed by high pressure tube twisting was analysed. It is shown that the grain refinement was in the steady state stage for a shear strain of 24 with a mean grain size of 120 nm.
Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine, Metz, France.|Laboratory of Excellence on Design of Alloy Metals for low-Mass Structures (DAMAS), University of Lorraine, Metz, France.
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Yuan
Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine, Metz, France.|Laboratory of Excellence on Design of Alloy Metals for low-Mass Structures (DAMAS), University of Lorraine, Metz, France.
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Brodu
Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine, Metz, France.|Laboratory of Excellence on Design of Alloy Metals for low-Mass Structures (DAMAS), University of Lorraine, Metz, France.
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Chen
Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine, Metz, France.|Laboratory of Excellence on Design of Alloy Metals for low-Mass Structures (DAMAS), University of Lorraine, Metz, France.
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Bouzy
Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine, Metz, France.|Laboratory of Excellence on Design of Alloy Metals for low-Mass Structures (DAMAS), University of Lorraine, Metz, France.
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Fundenberger
Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine, Metz, France.|Laboratory of Excellence on Design of Alloy Metals for low-Mass Structures (DAMAS), University of Lorraine, Metz, France.
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Toth
Al-Mg alloys; Transmission Kikuchi Diffraction (TKD); grain size; severe plastic deformation (SPD); spatial resolution