Electron Microscopy in Materials Science

Abstract

The materials scientist is concerned with relating microstructure and properties. In crystals, most of the important imperfections can only be observed by transmission through thin foils (T.E.M.), first accomplished by Heidenreich in 1949. The truly amazing growth of T.E.M. is due mainly to three factors: a) improvements in microscopes, b) techniques for foil preparation, c) interpretation of images using electron diffraction contrast theory. Almost all of T.E.M. has developed since 1955 as a result of the above factors.The following is a listing of some of the applications of Electron Microscopy.a) Observation and identification of lattice defects (dislocations, faults, small defect clusters, etc.).b) Crystallographic data from electron diffraction.c) Surface investigations, replication, reflection and scanning microscopy; fractography.d) Qualitative chemical analysis of characteristic x-rays emitted by the foil.e) Energy analyses for contrast and for identifying elements (by scanning microscopy also).f) In situ investigations of crystal growth, epitaxy.g) Examination of specimens at different temperatures; deformation, bombardment in situ.