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.