Fretting wear behaviors of Zr-4 alloy under different ions irradiation conditions

Studying the fretting wear behaviors of Zr-4 alloy under various ions irradiation conditions plays an important role in understanding the fretting damage source of cladding in nuclear reactor. In the study, fretting wear behaviors for Zr-4 alloy under various ions irradiation conditions were summarized as function of irradiation damage level, incident ion energy and ion species. The results demonstrate that increasing incident energy produced partially or completely amorphous phase in Zr-4 alloy. The friction coefficient and wear rate increase linearly with the increase of irradiation dose, but both are saturated at high irradiation dose, which can be attributed to the existence of an adiabatic or instantaneous recombination volume around the defect. Heavy ions irradiation with large mass and radius cause more and denser defects at shallower surface than ions with smaller radius, results in lower friction coefficient but increased the wear depth and wear rate. Conclusively, the friction coefficient and wear rate of Zr-4 alloy increase at the irradiation conditions investigated in this study. The dominant wear mechanism changes from adhesive wear and abrasive wear to fatigue wear and abrasive wear.