EBSD study of creep fracture surface in W-alloyed 9-12wt. percent Cr ferritic/martensitic steel P92

摘要

Ferritic/martensitic steels have a complex microstructure consisting of prior austenite grains (PAG) with a substructure of martensitic laths, blocks and packets. In recent tests, P92 specimens with fine PAG (diameter approx = 30 mu m) performed better under creep conditions than specimens made to the same compositional specification but with coarse PAG (diameter approx = 200 mu m). Laser scanning microscopy observations showed a difference in the morphology of the fracture surface between the two cases, suggesting a different fracture mechanism.