Quantification of the Laves phase in advanced 9–12% Cr steels using a standard SEM

Abstract

The precipitates in 9–12% Cr steels are usually quantified using the TEM/EFTEM method in combination with an image analysis routine. Because of the limited spatial area of investigation, a complete statistical quantification and description of Laves-phase precipitation, based on this method, is not possible. To compensate the limited magnification range, a technique has been developed to measure larger particles also using a standard scanning electron microscope (SEM). To enable the scanning of a large specimen area, a special preparation technique, in combination with a self-developed quantification routine, was applied. The growth and coarsening of the Laves phase was investigated for several advanced 9–12% Cr heat-resistant steels at 600 and 650 °C. The results are compared with published values obtained from (partly) different measuring techniques as well as to thermodynamic equilibrium calculations.