Novel martensitic steel for ultra-supercritical power rotors: enhanced high-stress creep resistance via multi-element MC carbides

This study presents the design of a novel heat-resistant steel derived from the P91 steel, achieved through precise control of C, Mo, V, and Cr contents, along with the addition of Ti and Ta. We found that the multi-component MC carbides possess exceptional thermal stability, maintaining a stable orientation relationship with the matrix following 650 °C creep testing. Additionally, these nanoscale needle-like carbides exhibit a pronounced dislocation pinning effect. Consequently, this steel demonstrates an extended rupture time under high stress conditions compared to conventional steels, highlighting its considerable potential for applications in ultra-supercritical power rotors. This study presents a novel heat-resistant steel used for ultra-supercritical power rotors, achieving enhanced creep resistance under high stress through multi-element nanoscale MC carbides with extremely high thermal stability.