Abstract:New reactor materials serve for a long time Under extreme loads and high temperatures. Creep resistance is the key service performance. In this paper, thermal creep experiments with different stresses (170-245MPa) were carried out at 1100K for the candidate material single crystal Mo-14Re alloy for advanced reactors. The creep time of the single crystal Mo-14Re alloy was obtained from 10 h to 780 h, and it was found that the creep of the single crystal Mo-14Re alloy conformed to the standard creep law, and the stress index n was 11.7. The creep mechanism is dislocation reinforcement, and with the increase of creep time, dislocation will form three dislocation derived structures: dislocation wall (substructure), dislocation network and dislocation cell. The above research provides a scientific basis for the research and development and safe service of advanced reactor materials.