Quantitative carbide analysis using the Rietveld method for 2.25Cr–1Mo–0.25V steel

It is usually difficult to quantitatively determine the mass fraction of each type of precipitates in steels using transmission electron microscopy and traditional X-ray powder diffraction analysis methods. In this paper the Rietveld full-pattern fitting algorithm was employed to calculate the relative mass fractions of the precipitates in 2.25Cr–1Mo–0.25V steel. The results suggest that the fractions of MC, M7C3 and M23C6 carbides were evaluated precisely and relatively quickly. In addition, it was found that the fine MC phase dissolved into the matrix with prolonged tempering.