Experimental and numerical simulation analysis on creep crack growth behavior of CLAM steel

The experiment and numerical simulation were performed to analyze the creep crack growth behavior of China Low Activation Martensitic (CLAM) steel under temperatures ranging from 500 °C to 600 °C with a step of 50 °C. The creep crack growth micro-mechanism under multiaxial state of stress was investigated with the compact tension (CT) specimens. The creep crack growth rates were simulated based on the Nikbin-Smith-Webster (NSW) model. The difference of the crack propagation behavior is correlated with the evolution of two types of precipitates: Cr-rich M23C6 and W-rich M6C phases. The coarsening of M23C6 carbides and the precipitation of M6C phase particles lead to dissolving of the solid solution elements and deteriorating the creep properties during the testing processes.