Effect of heat treatment on the microstructure and corrosion resistance of a Zr–Sn–Nb–Fe–Cr alloy

Zr–Sn–Nb–Fe–Cr zirconium alloy specimens treated in different ways were exposed to 0.01 M LiOH aqueous solution at 350 °C, 16.8 MPa. The microstructures of these specimens were investigated by transmission electron microscopy (TEM). It is found that the specimen treated by 800 °C/500 °C had best corrosion resistance among all the specimens. TEM analysis of this specimen showed that, in addition to Zr(Fe, Cr)2, there existed Zr–Nb–Fe type precipitates containing much more Nb element, which reduced niobium content in αZr solid solution and, therefore, resulted in an improvement in the corrosion resistance of Zr–Sn–Nb–Fe–Cr zirconium alloy.