Therefore, EBSD has become the most attractive, viable alternative for measuring grain size, even without considering the vast amount of additional microstructural information that the technique can provide. In addition, as the trend is towards nano scale materials, there is a limit to the grain size which can be detected by LOM (as governed by the wavelength of visible light). However, this etching can be influenced by the existing microstructure in the sample, which can be problem for fine structured materials. This optical technique usually requires a chemical etching of the surface in order to highlight the grain boundaries. Traditionally grain size was measured using light optical microscopy (LOM) and some of the grain size standards still reference this method. To accurately measure grain size, it is imperative that all of the grain boundaries are firstly defined and then reliably detected. EBSD is an ideal technique for determining this grain size, as it combines exceptional spatial resolution and the capability to analyse large areas (and hence many 1000s of grains) very quickly with a quantitative rigour that is missing from other techniques. via the Hall-Petch relationship where strength is inversely dependent on the square root of grain size). Grain size is an important characteristic used in understanding the development, engineering and potential failure in materials, not least because the mechanical and physical properties of metallic materials are often related to their grain size (e.g. In the tabs below we look at 4 main categories of EBSD data representation, namely grain size, texture, boundaries and maps, giving examples of how these can be used to highlight and understand aspects of a sample’s microstructure.Ī grain can be considered as a three-dimensional crystalline volume within a specimen that differs in crystallographic orientation from its surroundings but, internally, has little orientation variation. Texture (or crystallographic preferred orientation).The spatially-linked crystallographic orientation and phase information acquired with EBSD can be processed to deliver information about the sample, which in turn can be linked to the materials processing history and physical properties. Unlike many associated electron microscopy techniques, such as energy dispersive X-ray spectrometry (EDS), EBSD analyses typically involve a significant time processing and interrogating the datasets away from the microscope. The data collected with Electron Backscatter Diffraction (EBSD) contain a wealth of sample information which can be processed using a suite of analytical tools to visualise and represent microstructure at the micro and nano scale. Displaying Electron Backscatter Diffraction (EBSD) Data
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