Improving corrosion resistance of zirconium alloys

摘要

Zr alloy tube has a metallurgical gradient, the internal circumference having a relatively low corrosion resistance and the external circumference having a relatively high corrosion resistance and consisting of a transformed alpha plus beta or transformed alpha prime crystalline structure. The tube may have a protective lining (pref. of Zr metal) bonded to its interior surface. Also claimed is a method of improving the corrosion resistance of zirconium alloys by heating to the alpha prime phase region and quenching to retain the metallurgical state of improved corrosion resistance. The tube is useful as nuclear fuel element cladding for boiling water reactors. An external surface, which is more resistant to oxidn. by hot water and steam than that of conventional tubes, is formed while maintaining the desired mechanical properties (i.e. high ductility) into the bulk of the tube.