Banded structures in dual-phase steels - A novel characterization method

A simple to implement and original automated method is presented to quantify the intensity and wavelength of banded structures, i.e. microstructures presenting irregular and parallel bands enriched in a given phase. This method is based on the analysis of the covariance function of binary images. It is firstly tested on model representative images. It is compared with a conventional method derived from the ASTM E-1268 standard and appears to present a higher robustness with regard to preparation artifacts. Then, it is applied to real microstructures of dual-phase steels, which show more or less regular martensite-enriched bands in a ferrite matrix. The method is capable of efficiently discriminating dual-phase microstructures resulting from different thermo-mechanical routes.