Meaning
Microstructural characterization techniques provide detailed information about the crystallographic orientation of grains within a polycrystalline material. Election backscatter diffraction is a scanning electron microscopy based method used to map the texture and phase distribution of metal alloys or ceramics. It relies on the interaction of a primary electron beam with a tilted specimen to produce diffraction patterns that reveal the spatial arrangement of atoms.
Analysis Mechanism
Pattern formation occurs when electrons scattered from the sample surface undergo Bragg diffraction at specific angles. Automated software captures these Kikuchi patterns and indexes them against a known lattice database to identify the local crystal orientation and the symmetry of the phase. Higher tilt angles, usually around seventy degrees, optimize the signal.
Information Yield
Data collection produces grain maps that show the size, shape, misorientation and lattice strain of individual crystals. Scientists use election backscatter diffraction to quantify the extent of plastic deformation and the presence of twin boundaries.
Application Scope
Industrial laboratories utilize this technique to troubleshoot failures in automotive components or aerospace fasteners. By observing the orientation of grains near a fracture surface, technicians determine if a failure resulted from fatigue or stress corrosion cracking. This process requires a flat, polished surface to prevent topographical shadows from obscuring the diffraction patterns.
