Quantitative Phase Analysis of TRIP Steels

—The phase composition of a VNS9-Sh TRIP steel strip 0.8 mm thick is determined using layer-by-layer X-ray diffraction (XRD) analysis using Mo, Co, or Cu radiation. The influence of the type of radiation on the efficiency of quantitative phase analysis of thin-sheet TRIP steels is examined using the obtained results. The parameter “information depth” is accepted as an efficiency characteristic. The information depth is the layer thickness the scattering intensity from which amounts 90% of the total scattering intensity. It is recommended to use Cu radiation providing an information reflection depth of 1.8–3.4 μm, which is comparable with the gradient surface layer thickness, in order to estimate the volume fraction of phases over the cross section of thin-sheet TRIP steels, whose main changes in the phase composition occur in a surface layer ≈5 μm thick. The information depth is 5.8–11.1 and 9–17.5 μm for Co or Mo radiation, respectively.