Creep rates and strengthening mechanisms in tungsten-strengthened 9Cr steels

Abstract The creep deformation behavior has been investigated for simple 9Cr–W and solute modified 9Cr–WVTa steels containing high W, where Fe 2 W Laves phase precipitates during creep. Creep tests were carried out at 823, 873 and 923 K for up to 15 000 h. The precipitation of Fe 2 W effectively decreases a minimum creep rate, but the large coarsening of Fe 2 W promotes the acceleration of creep rate after reaching a minimum creep rate. As a result, the effect of Fe 2 W on the extension of creep rupture time is rather small. The fine MC carbides are significantly effective for the stabilization of lath martensitic microstructure.