The oxidation of the following zirconium alloys in water at 680 deg F is reported: Zircaloy-2, Zr--Cr-- Te, Zr-Nb-Te, Zi--Sn-Te, Zr--Sn-Ge, Zr--Sb-Ge, Zr-- Sb-Te, and Zi-Sb--Nb. The tensile properties of Zircaloy-2, ZrCr-Te, and Zr-Nb-- Te alloys at room temperature and 680 deg are given. (N.W.R.).

On the basis of 4800 hr exposure to 680 l F water, a number of ternary compositions were shown to have corrosion resistance superior to Zircaloy-2. In addition, the strength and hydrogen pickup properties of the alloys were generally improved over Zircaloy-2. The promising alloys were based on the binary materials Zr- 1Sb, Zr- 1Cr, Zr0.5Nb, and Zr-0.5Sn to which small percentages of Te, Ge, Cr, or Fe were added. At present, 680 l F water corrosion data for an exposure time of 5000 hr are available for the modified ternary alloys. Development of materials for potential service in 750 and 900 l F steam proceeded in a manner similar to that for 680 l F water application. On the basis of corrosion resistance and strength, the alloys Zr3Cr- 1Fe, Zr-3Cr- 0.25Te, and Zr- 1V- 1Fe were considered highly promising and initially acceptable. However, hydrogen pickup properties, which were about the same as Zircaloy-2, were judged as unacceptable. In an attempt to improve this characteristic as well as to further enhance corrosion resistance and strength, an additional series of ternary alloys was prepared. The compositions studied in 900 l F steam did not exhibit satisfactory corrosion resistance. (P.C.H.).

Progress reported includes the selection of 15 ternary bases for further study in steam or water. About 75 compositions were prepared and are being arc- melted for fabrication into corrosion specimens. Investigations of Zr purity and heat treatment effects on corrosion are being continued. Included are data from corrosion tests on binary alloys with superheated water and steam, and a list of alloys for initial investigation based on results of corrosion screening tests. (J.H.D.).

Corrosion and hydrogen pickup data are available on ternary alloys in 680 deg F water for an exposure time of 4800 hr. 1n general, the longer the time to transition, the lower the post-transition corrosion rate was. Ternary zirconium alloys were exposed to 750 deg F steam for a period of 3000 hr. Weight gain and hydrogen pickup values were.