Microstructural characterization of dual phase steels by means of electron microscopy

Dual phase (DP) steels have a low yield strength due to the soft ferrite matrix and a high tensile strength due to the hard dispersed martensite second phase islands. This makes them excellent steels for use in light weight automobile structural parts. A profound understanding of microstructure-properties relationships of advanced high strength steels is of crucial importance to the rational development of these steels. This demands the ability to perform advanced quantification of the complex multiphase microstructure, addressing the full range of microstructural properties that are relevant to the macroscopic mechanical behaviour. The ferrite-martensite microstructure will be studied by means of Light Optical Microscopy, Scanning Electron Microscopy and Electron BackScatter Diffraction. The martensite fraction in ferrite-martensite DP steels will be measured both on a FEG-SEM and a LaB6-SEM. The influence of the microscope resolution on the determinatio