SFCM 11/12 23: ELECTRON CHANNELING AND DIFFRACTION FOR ORIENTATION ANALYSIS AND DEFECT IMAGING скачать в хорошем качестве

SFCM 11/12 23: ELECTRON CHANNELING AND DIFFRACTION FOR ORIENTATION ANALYSIS AND DEFECT IMAGING

MICROSCALE CHARACTERIZATION IN THE SEM: ELECTRON CHANNELING AND DIFFRACTION FOR ORIENTATION ANALYSIS AND DEFECT IMAGING Miércoles 18 de Abril de 2012. MARTIN A. CRIMP DEPARTMENT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE, MICHIGAN STATE UNIVERSITY, USA Electron diffraction has been used for many years to characterize materials at the nanoscale. Historically these studies have been carried out using transmission electron microscopy (TEM), which not only allows diffraction studies based on selected area electron diffraction (SAED) and convergent beam electron diffraction (CBED), but also imaging and defect analysis based on diffraction contrast. A primary difficulty in using TEM has been the limitations imposed by the preparation and use of TEM thin foils. As an alternative approach, scanning electron microscopy (SEM) offers the ability to carry out a number of different types of electron diffraction studies on bulk specimens. Selected area channeling patterns (SACPs) and electron back scattered diffraction (EBSD) patterns can be used to measure crystalline orientations at spatial resolutions in the micron range. Electron channeling contrast imaging (ECCI) can be used to image nanoscale crystalline defects such as dislocations and deformation twins. In many respects, the image formation in ECCI is analogous to diffraction contrast in TEM, and similar contrast analyses can be carried out. This talk will cover the basic processes of electron diffraction and channeling phenomena in bulk samples, along with the experimental parameters involved with carrying out electron diffraction/channeling analyses. A number of examples will be presented that illustrate the capabilities and advantages of using ECCI for defect imaging and analysis including the examination of defect structures at crack tips and edges, the study of defect generation in in-situ loaded samples, and the analysis of deformation transfer and nucleation of microcracks at grain boundaries. Additionally, examples of the application of ECCI to the non-destructive imaging of dislocations in electronic devices will be presented.