16 - Application of modern transmission electron microscopy (TEM) techniques to the study of phase transformations in steels

Abstract

Transmission electron microscopy (TEM) is the most widely used technique for studying all aspects of phase transformations in steels over the length scale range 1–100nm. The capabilities of modern TEM include aberration correction (spherical and chromatic), energy-filtered imaging (EFTEM), convergent beam diffraction (CBED), annular dark field imaging (ADF) and microchemical analysis by X-ray energy dispersive spectroscopy (XEDS) and electron energy loss spectroscopy (EELS). Nevertheless, the majority of TEM studies on phase transformations in steels continue to be conventional TEM (CTEM). This chapter reviews the wide application of TEM to this subject. It includes brief descriptions of sample preparation techniques and CTEM. The main body of the chapter considers modern TEM techniques and emerging TEM techniques, which offer new capabilities. For complete characterization of microstructures at all relevant length scales, complementary techniques such as atom probe tomography (APT), electron back scattered diffraction (EBSD) and bulk diffraction techniques (synchrotron X-ray and neutron) must be utilized, in addition to TEM.