Laves phase evolution in 10Cr-3W-3Co steel during thermal exposure and creep

•Comparison of thermal and creep exposure – influence on Laves phase (LP) growth.•Different kinetics of LP precipitation – slower rate of LP growth during early stages of creep.•Much less elongated LP particles formed during creep than during thermal exposure.•The state of matrix recrystallization might be the reason for the differences in the LP content and morphology. The formation of Laves phase was studied in experimental 10Cr-3 W-3Co creep-resistant steel. The steel was exposed to the temperature of 650 °C, and just thermal and creep exposure was compared. Laves phase content, particle size, and morphology were quantitatively analysed by image analysis of micrographs. Significant differences were observed between the creep and thermal exposure. Thermal exposure resulted in fine Laves phase particle nucleation and their gradual coarsening. On the other hand, creep exposure induced the formation of coarse particles from the early stages of exposure. The differences seem to originate in a different state of the matrix, where martensite crystal boundaries facilitate the precipitation of fine Laves phase particles.