On the microstructural evolution and room-temperature creep behaviour of 9%Cr steel weld joint under prior creep-fatigue interaction

The high-temperature creep-fatigue (CF) interaction on the service damage of P92 welded joint was uncovered based on the evolution of local creep behaviour by nanoindentation. The creep resistance and high-angle grain boundary (HAGB) distributions of the different regions of welded joint were investigated for the specimens under individual creep (stress relaxation [RS]), fatigue and CF loadings interrupted at lifetime fractions of 10%, 20%, 30%, 60% and 100%. According to structure evolution including the changes of HAGB and dislocation densities during high-temperature deformation, the local variation mechanism of creep behaviour at different microstructural zones was systematically discussed.

Automated summary

This study investigated the influence of high-temperature creep-fatigue interaction on the service damage of P92 welded joint based on the evolution of local creep behavior by nanoindentation. The variations in creep resistance and high-angle grain boundary distributions in different microstructural zones of the welded joint under individual creep, fatigue and creep-fatigue loadings were systematically discussed.