Effect of heat treatment on the Nb distribution and corrosion resistance of Zr-Sn-Nb-Fe zirconium alloy

After being treated in different ways, Zr-Sn-Nb-Fe alloy specimens are exposed in 0.01mol/L LiOH aqueous solution at 350°C under 16.8 MPa. The examination of microstructures and second phase particles (SPPs) of these specimens was carried out by high-resolution transmission electron microscopy (HR-TEM). The specimens treated at 800°C before the final cold rolling have a better corrosion resistance than those treated at 680°C, and the specimens treated at 500°C, after the final cold rolling, have a better corrosion resistance than those treated at 560°C. TEM examination shows that the SPPs existing in the 800°C/500°C specimen, which has the best corrosion resistance, contains a lot of Nb element, which results in the reduction of the niobium content in the α-Zr solid solution.