Effect of Alloying Elements on Creep Behaviors of Zr Alloys

Zr alloys are widely used as core structural materials for nuclear reactors due to their advantages of low thermal neutron absorption cross-section, corrosion resistance, high temperature resistance, and excellent mechanical properties. Zr alloys undergo creep deformation because of the extreme environments of high temperature, high pressure, corrosion, and neutron irradiation in nuclear reactors, which affect the performance of the fuel rods; thus an excellent creep resistance is one of key prerequisites to ensure the effective operation of fuel assembly. Alloying is currently the main strategy to develop creep-resistant Zr alloys. In this paper, we review the creep mechanism of typical Zr alloys used in nuclear reactors, summarize the effects of key alloying elements on the macroscopic creep behaviors of Zr alloys, analyze the changes in the creep microscopic mechanism related to the interaction between dislocations and alloying elements, and finally discuss the development status of this field. It is desirable to develop an effective physical model to predict the creep behaviors of Zr alloys in nuclear reactors based on the off-reactor experimental results.