THE APPLICATION OF SCANNING ELECTRON-MICROSCOPY TO FRACTOGRAPHY

Many failures involve fracture, and determination of the fracture process is a key factor in understanding the failure. This is frequently accomplished by characterizing the topography of the fracture surface. Scanning electron microscopy has a prominent role in fractography due to three features of the scanning electron microscope (SEM): high resolution, great depth of field, and the ability to obtain chemical information via analysis of the X-rays generated by the electrons. A qualitative treatment is presented of the interaction of electrons with a sample and the effect of the SEM operating parameters on image formation, quality, and X-ray analysis. Fractographs are presented to illustrate these features of scanning electron microscopy and to illustrate the limitations and precautions in obtaining fractographs and X-ray analyses. The review is concluded with examples of fracture surface features of metallic, ceramic, and polymeric materials.