Papers by Author: Claude Esling

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Authors: Liang Zuo, Claude Esling, J. Muller, Emmanuel Bouzy
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Authors: Gang Wang, Shi Ding Wu, Yan Dong Wang, Ya Ping Zong, Claude Esling, Liang Zuo
Abstract: Equal channel angular extrusion (ECAE) is an effective means of producing ultrafine-grained materials with extraordinary mechanical properties. Texture evolution and microstructure in pure copper single crystals processed by ECAE for up to five passes via route C are investigated to understand mechanisms of plastic deformation and grain refinement during ECAE. The experimental textures after the third pass ECAE process recovers that after one pass ECAE process. The main textures approaches a stable one after four passes of ECAE process via Route C while the intensity of main texture components decreases gradually. Local TEM-OIM measurements shows that grain subdivision in ECAE-processed samples occurs with the formation of many low angle grain boundaries.
929
Authors: Yu Dong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Abstract: In this paper, some of our recent results in phase equilibrium, microstructure, texture and precipitation resulting from the application of an external high magnetic field during diffusional phase transformation in both medium carbon and high carbon steels have been summarized Their potential engineering applications are foreseen.
202
Authors: Zong Bin Li, Yu Dong Zhang, Claude Esling, Hao Yang, Ji Jie Wang, Chang Shu He, Xiang Zhao, Liang Zuo
Abstract: For off-stoichiometric Ni2MnGa ferromagnetic shape memory alloys, a large shape change could be induced through the rearrangement of martensitic variants under an external magnetic field. Insight into the orientation relationships of martensitic variants and the characteristics of variant boundaries is thus essential for understanding the magnetic shape memory performance. In this paper, a thorough crystallographic investigation was made on the incommensurate 7M modulated martensite in one polycrystalline Ni50Mn30Ga20 alloy by means of X-ray diffraction and SEM electron backscattered diffraction (EBSD). Locally, there are four differently-oriented martensitic variants, being twin related to one another. The twin interface planes are coherent and they are in coincidence with the respective twinning planes (K1). A primary exploration was performed to improve the microstructure by repeated magnetic field training during phase transition. The present investigation could offer useful guidance to develop specific technique for microstructure optimization.
1879
Authors: Yu Dong Zhang, Zong Bin Li, Claude Esling, Xiang Zhao, Liang Zuo
Abstract: In the present work, we summarized two calculation methods to determine some specific crystallographic elements based on electron diffraction orientation measurements by SEM/EBSD or TEM. The first one is to determine the twin type and twinning elements of crystal twins based on the minimum shear criterion, using the experimentally determined twinning plane for Type I twin and compound twin or twinning direction for Type II twin as initial input. The method is valid for any crystal structure. The second one is one to determine the plane indices of the faceted interfaces where the orientation relationships (ORs) between the adjacent crystals are reproducible. The method requires one prepared sample surface instead of two perpendicular surfaces. These methods are expected to facilitate the related microstructural characterizations.
2674
Authors: Claude Esling, Yu Dong Zhang, Jacques Muller, Xiang Zhao, Liang Zuo
Abstract: In the present work, we summarize three calculation methods to determine some specific crystallographic elements based on electron diffraction orientation measurements by SEM and TEM. The first one is to determine the plane indices of the faceted interfaces where the orientation relation¬ships (ORs) between the adjacent crystals are reproducible. To acquire the orientation data, we need to prepare only one sample surface but not two perpendicular sample surfaces as usually required in the standard double trace method. The second is to characterize the surface crystalline planes and directions of a faceted nano-particle under TEM imaging and diffraction mode. With the determination of the edge trace vectors and then the plane normal vectors in the screen coordinate system of TEM, their Miller indices in the crystal coordinate system can be calculated through coordinate trans¬formation. The third method is to determine the twin type and the twinning elements based on the orientation information acquired by SEM EBSD measurements from the two twinned crystals through misorientation calculations. These methods will facilitate related studies.
11
Authors: Yu Dong Zhang, Chang Shu He, X. Zhao, Yan Dong Wang, Liang Zuo, Claude Esling
Abstract: The Weiss model is extended by substituting the molecular field coefficient lwith a short-range-ordering coefficient g valid around and above Tc. The temperature variations of susceptibility of fcc Fe are calculated with a band model. Based on the above models, the phase equilibrium diagram of Fe-C binary system under a magnetic field is calculated.
187
Authors: Chang Shu He, Yu Dong Zhang, X. Zhao, Liang Zuo, Claude Esling
Abstract: High magnetic field is applied with the field direction parallel to the rolling direction during annealing of a cold rolled IF steel sheet. Results of X-ray ODF analysis show that, magnetic field annealing retards the normal recrystallization texture evolution for the IF steel sheet. It is worth noting that an abnormal increase of orientation intensity at {100}<110> is found after magnetic annealing for 25min at 650°C. When the magnetic field strength is increased from 10 Tesla to 14 Tesla, the a-fiber is further strengthened, especially the {100}<110> component. Combined with EBSD analysis results, it is considered that the magnetic field does not change the mechanism of recrystallization texture evolution for the IF steel sheet in the present case.
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