Precise elemental composition analysis during EBSD measurements

Instruments used

EDAX^® Pegasus EDS – EBSD System and EDAX APEX™ Advanced Software

Background

For many engineering materials, it is critical to understand the relationship between functional properties and a material’s composition and microstructure. Therefore, energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) in the scanning electron microscope (SEM) form essential methods of characterization in a material scientist’s toolbox. It has long been recognized that the simultaneous collection and analysis of the EDS and EBSD signals from multiphase materials is desirable due to the elimination of ambiguity and error in interpretation and a reduction in data collection and analysis times by an order of magnitude. However, it is often assumed that the experimental conditions used for EBSD analysis—a sample tilted to 70° and high beam currents—preclude quantitative composition analysis by EDS. Conventionally, quantitative EDS analysis is assumed to require low x-ray count rates and a flat specimen at 0° tilt so that all x-rays reaching the detector are recorded accurately, and the effect of x-ray re-absorption within the sample may be accounted for. This lack of quantitative compositional information prevents a complete understanding of the data collected from the analyzed material.