Microstructure evolution analysis on creep behavior of Grade 91 steel under multiaxial state of stress

Creep tests of Grade 91 heat-resistant martensitic steel under multiaxial state of stress were conducted at 923K with stress ranging from 125 to 200MPa. The test results showed that the creep time of Grade 91 steel increases with the decreasing of applied stress. The microstructure evolution during creep of Grade 91 heat-resistant martensitic steel was investigated based on the optical microscope and scanning electron microscope analysis.