Cette dégradation est d’autant plus marquée que l’anisotropie d’une soudure est fortement inhomogène en raison de la croissance dendritique de la matière au moment de son refroidissement. C’est notamment le cas des structures anisotropes, comme les soudures en acier du domaine nucléaire, où la méconnaissance de l’anisotropie au moment de l’inspection peut conduire à des images très dégradées et inexploitables. Finally, it should also be stressed that the experiments in this work were carried out in a standard BiCMOS pilot-line, making this study unique, as its results might directly pave the way to further graphene integration and graphene-based device prototyping in mainstream Si technologies.Įn contrôle non-destructif par ultrasons, la qualité de l’imagerie échographique repose sur l’adéquation entre le modèle direct de propagation des ondes élastiques et la propagation dans le milieu physique. To achieve the growth of the highest quality of graphene, this work focuses on the investigations of various nucleation and growth mechanisms, substrate–graphene interfaces, effects of different substrate orientations, and detailed microscopic and macroscopic characterization of the grown films. In this PhD work, 8-inch scale graphene synthesis is attempted on alternative substrates such as epitaxial Germanium on Si and polycrystalline Nickel on Si. Though large-area graphene can be achieved on substrates like copper, platinum, silicon carbide, or single-crystal Ni, however, high growth temperatures, unavailability of large scale, or contamination issues are the main drawbacks of their usage. Among them, high-quality and wafer-scale graphene synthesis on CMOS compatible substrates is of the highest importance. At this point, the implementation of graphene into Silicon (Si) semiconductor technology is strongly dependent on several key challenges. Close parallelism between the polished and original surfaces was verified.ĭue to the unique electronic band structure, graphene has opened the great potential to extend the functionality of a large variety of graphene-based devices in health and environment, energy storage, or various microelectronic applications, to mention a few. A resolution of 100 nm in the total removed layer was attainable via careful control of the polishing parameters. At the subsurface region, exposed by on-top mechanical polishing, the flatter nature of the polished surfaces allowed the acquisition of EBSD patterns with enough quality for microtexture analysis. We observed that as-nitrided virgin surfaces were not suitable for EBSD characterization, due to intense surface roughening, which was induced by the nitriding process itself. The suitability of the polished surfaces for conducting EBSD characterization was assessed through an analysis of both the surface roughness (appraised by atomic force microscopy) and the quality of the Kikuchi diffraction patterns. Noticeable fractions of equiaxed grains surrounded by low angle boundaries (misorientation and respectively.Ībstract This contribution reports on an experimental polishing procedure, that is comprised of early grinding in Al2O3 slurries and late polishing in colloidal silica, which is used for preparing the nitrided region of a plasma nitrided austenitic stainless steel, for crystallographic analysis via electron backscatter diffraction (EBSD). The results show smaller grains after the 1 st ARB pass, with substantial grew after the 2 nd ARB pass due to the higher temperature owing adiabatic warming. Two ARB cycles were performed in this study, at room temperature, and the samples were characterised by EBSD. This paper presents an Electron Backscatter Diffraction (EBSD) analysis of the effect of temperature on grain size, grain boundaries and texture of Aluminium Alloy 1050-H4 during Accumulative Roll Bonding (ARB). In summary, an outlook for EBSD technique was provided. Sample preparation methods were reviewed and EBSD ap-plication in conjunction with other characterization techniques on a variety of materials has been presented for several case studies. Image quality, resolution and speed, and system calibration have also been discussed. ![]() Principles of crystal diffraction with description of crystallographic orientation, orientation determination and phase identification have been described. Key milestones re-lated to technological developments of EBSD technique have been outlined along with possible applications using modern EBSD system. Captured patterns can then be used to determine grain morphology, crystallographic orientation and chemistry of present phases, which provide complete characterization of microstructure and strong correlation to both properties and performance of materials. Electron Back-Scatter Diffraction (EBSD) is a powerful technique that captures electron diffraction patterns from crystals, constituents of material.
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