Elastic and Plastic Strain Measurement Using Electron Backscatter Diffraction Technique: The Influence of Sample Preparation

In materials science, knowledge about elastic and plastic strain, as well as their distribution in crystalline materials, is critical when studying phenomena such as stress fatigue, corrosion cracking, and formability. In semiconductor devices, elastic and plastic strain can introduce crystallographic defects and cause fracture and delamination, which can dramatically change electrical properties and device reliability. For these reasons, the measurement of plastic and elastic strain was widespread in industrial and academic environments in the past decade. Many techniques have been developed and used for plastic and elastic strain study In microscopy and microanalyses, one of the techniques used for deformation structures characterization is electron backscatter diffraction (EBSD). The EBSD plastic strain measurement techniques rely on recording changes in EBSD pattern quality Recently, the EBSD technique was applied to elastic strain measurements. This approach is based on cross-correlation analysis of high resolution EBSD patterns. The technique measures lattice distortion-related differences between EBSD patterns obtained from the same grain and it is known as HR-EBSD Both strain studies by EBSD and HR-EBSD are very sensitive to diffraction pattern quality. Aside from intrinsic instrumentation limitations, sample preparation factors prominently into accuracy and precision attained in HR-EBSD strain analyses. Surface contamination, oxidation, crystal lattice damage, and plastic deformation must be avoided during sample preparation to obtain accurate and precise measurements.