Fretting friction wear behavior of zircaloy and NI-based GH4169 alloy

The fuel rod tubes are disturbed under the condition of micro-vibration when the coolant flow pasts the surface of the fuel rod tubes from the bottom to the top during the operation of nuclear reactors, which can cause the fretting wear at the contact area of the frame spring and the tube cladding, and thus radio-active products might be leaked out under certain serious conditions, which will result in the shutdown of nuclear reactors, influencing its safety. The fretting wear behavior of Zirconium alloy Zr-4 and N36 mated with Ni-based GH4169 alloy was investigated in this work. The worn surfaces were examined with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and 3D Microscopy. The obtained results showed that the friction efficient increases with the load increasing, and the Zr-4/Zr-4 has the maximum friction efficient, while the GH4169/N36 has the lowest friction efficient. Meanwhile, the preliminary oxidation has great influence on the friction behavior, and the friction coefficient of the pre-oxidized samples is higher than that of the non-pre-oxidized. (author)