Experimenting with Grain Contrast Imaging

Metallography, etching, and optical microscopy are the most common methods used to evaluate the microstructure of metallic materials (such as structural and specialty alloys). However, etching can be problematic for components with multiple metals (such as claddings) and certain multiphase materials, where differential etching rates may obscure critical microstructural features. In instances where etching is not a viable option, grain contrast imaging utilizing a scanning electron microscope (SEM) provides an alternative for microstructure evaluation without requiring etching. This presentation will explore the principles of grain contrast imaging, imaging parameters, sample preparation techniques, and a little physics on electron-matter interactions, while we discuss grain contrast imaging in the SEM.