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Electron Backscatter Diffraction (EBSD) is a destructive, surface-specific technique that measures accurately crystallographic orientations within a scanning electron microscope (SEM). From this data we can infer elastic properties, calculate levels of stress and measure microstructural properties such as the size and aspect ratios of grains. The Electromagnetic Acoustic Transducer (EMAT) is a non-contact, ultrasonic transducer that is suitable for operation on electrically conducting materials such as Aluminium and Steel. This paper highlights some of the work carried out using EBSD as a technique to validate EMAT measurements on rolled sheet to determine microstructural properties such as grain size and aspect ratios via shear wave through-thickness attenuation, and other macroscopic properties like average crystallographic texture. Work is also presented on another application for EBSD, in that it can be used to confirm whether an NDE technique is in fact nondestructive. Here we look at the case of a Nd:Yag pulsed laser irradiating a sample, in the ablative/thermoelastic regime boundary. [ABSTRACT FROM AUTHOR]

Determining the Orientation Distribution Function (ODF) accurately and quickly in a non-destructive manner has many benefits and applications within industry. The ODF is essentially a quantitative description of the existence of anisotropy, or texture, within a metal sheet. The anisotropy can be seen experimentally by the variation in Lamb wave velocities in the plane of the sheet as a function of angle to the Rolling Direction. The anisotropy can be quantitatively described by the Orientation Distribution Coefficients (ODCs) W400, W420 and W440. Electron Backscatter Diffraction (EBSD) is a technique performed in a SEM. It infers the crystallographic directions of crystals near-surface, and can be applied to a number of samples. It enables the accurate quantitative and qualitative description of microstructural properties such as grain size. By manipulating the Bunge-Euler angle data given by the EBSD technique, here we describe a method to extrapolate the effective elastic constants for Aluminium sheet, and go on to generate a method to predict a Lamb wave velocity profile as a function of angle in a directly comparable format to that measured using a commercially available EMAT-EMAT S0 Lamb wave velocity measurement system. Results show a very good correlation between the predicted velocity trace from EBSD compared to that measured ultrasonically, and hence the respective ODCs, except in the cases where surface to bulk texture inhomogeneity exist. [ABSTRACT FROM AUTHOR]

Electron Backscatter Diffraction (EBSD) is a microscopic technique that provides detailed crystallographic orientation information for given samples. It enables the quantitative calculation and visualization of important microstructural properties such as grain size, aspect ratio and the average grain orientation of the aggregate, commonly known as the Orientation Distribution Function (ODF). In order to validate an ultrasonic technique to quantitatively describe texture we are correlating ultrasonic velocity measurements with results from EBSD. The velocity variations as a function of angle from the Rolling Direction in sheet samples are dependent on such quantities measurable by the EBSD technique. We describe here a modified technique to extrapolate the three independent Orientation Distribution Coefficients (ODCs) W400, W420 and W440 for cubic structures from the Bunge-Euler angle data determined through EBSD scans as a description of texture within the sample. EBSD results, taken from through-thickness scans to eliminate the errors that arise with surface-to-bulk inhomogeneity, for rolled aluminium sheets are discussed compared to the ODCs obtained using an ultrasonic EMAT-EMAT S0 Lamb wave velocity measurement system. [ABSTRACT FROM AUTHOR]

Electron Backscatter Diffraction (EBSD) is a microscopic technique that provides detailed crystallographic orientation and microstructural information, allowing for accurate measurement of such properties like average grain size. In order to validate and better understand what information an ultrasonic technique can give us we are correlating the ultrasonic measurements with those from EBSD. It generates an appreciation of the limitations of both techniques, and what each can reasonably deliver. We describe a technique to extrapolate the three independent orientation distribution coefficients (ODCs) for cubic structures W400, W420 and W440 from the Bunge-Euler angle data from EBSD scans. Preliminary EBSD results for thin rolled aluminium sheet are discussed and compared to the ODCs determined on the same sample using an ultrasonic EMAT-EMAT S0 Lamb wave measurement system. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]