Proton irradiation effects on the precipitate in a Zr-1.6Sn-0.6Nb-0.2Fe-0.1Cr alloy

The behavior of the precipitate in a Zr-1.6Sn-0.6Nb-0.2Fe-0.1Cr alloy under a 2 MeV proton irradiation was studied by transmission electron microscopy (TEM). The plan-view TEM specimens were prepared by a focused ion beam (FIB) lift-out method. It is confirmed that the Zr(Fe,Cr,Nb)2 precipitate with the hexagonal close packed (hcp) structure is the major secondary phase particle (SPP) in this zirconium alloy. At irradiation temperature of 360 °C, the Zr(Fe,Cr,Nb)2 precipitate starts to be partially amorphized when the zirconium alloy was irradiated to 3.9 dpa, and was completely amorphized at 8.2 dpa. The mechanism for the Zr(Fe,Cr,Nb)2 precipitate amorphization under proton irradiation is attributed to the Fe diffusion from the Zr(Fe,Cr,Nb)2 phase to the zirconium alloy matrix. The current research indicates that the Zr-1.6Sn-0.6Nb-0.2Fe-0.1Cr alloy has lower irradiation resistance than that of Zircaloy-4, but the results still need to be further verified by its irradiation resistance with respect to neutron irradiation.