Wear behavior of Zirconium-4 alloy after different irradiation damage level

Abstract Effect of neutron irradiation damage on fretting wear of Zirconium-4 alloy was simulated using ions irradiation in previous work, but the evolution of structure and tribological properties as a function of irradiation fluence is not considered. Therefore, in this study, 3 MeV Fe11+ ions were used with the irradiation fluence from 4.31×1013 to 4.31×1015 cm-2, corresponding to the damage level from 0.1 to 10 dpa. The results show that fine grains, higher density of dislocations, point defects as well as disorder area were observed in damage zone. The increased grain boundaries caused by small grain together with the irradiation-induced defects served as the obstacles of dislocations, leading to the higher hardness. The friction coefficient increases from original 0.6 to 1.2 after damage level to 0.5 dpa and turn to saturation with further increasing the damage to 10 dpa. Obvious wear aggravation as similar change tendency as the friction coefficient after 0.5 dpa damage level was also observed. These changes in wear behaviors of Zirconium-4 alloy after irradiation can be attributed to the additional energy dissipation caused by surface fracture, the sharper wear debris and the increase of friction force resulted from the obstruction of dislocation movement in the irradiated sample.