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.

A number of zirconium ternary alloys have been developed for service in 680 deg F water which meet objectives of corrosion resistance, strength, and hydrogen pickup. Ternary alloys have been developed for service in 750 deg F steam which are superior to Zircaloy-2 regarding corrosion resistance and strength. (R.J.S.).

Experiments concerned with the development of zirconium-base alloys having corrosion resistance and strength superior to Zircaloy-2 and/or the development of materials of equivalent corrosion resistance but exhibiting enhanced strength are presented. After 3000 hr exposure to 680 deg F water, binary zirconium alloys showed corrosion resistance superior to Zircaloy-2. Alloys considered promising and which offer the highest chance of success are based on the binary compositions Zr--1Cr, Zr--ISb, Zr--O.5Nb, and Zr--O.5Sn with small additions of Te, Ge, Cr, or Fe. Alloys containing relatively high percentages of solute elements did not exhibit satisfactory corrosion properties. Corrosion data on experimental alloys in 750 deg F steam indicate a few highly proising and initially acceptable materials, which are Zr--3Cr --lFe, Zr--3Cr-- 0.25Te, and Zr--lV--lFe. Thus far the corrosion resistance is better than Zircaloy-2 and the higher alloy content indicates enhanced elevated temperature strength. (P.C.H.).

A number of ternary compositions were developed for service in 680 deg F water which meet the objectives of a zirconium alloy improvement program on the basis of corrosion resistance, strength, and hydrogen pickup. These are compositions based on Zr-- 1Sb, Zr-- 1Cr, Zr--0.5Nb, and Zr--0.5Sn with minor additions of Te, Ge, Cr, or Fe. In 750 deg F steam, the materials Zr--3Cr-1Fe, Zr--3Cr--0.25Te, and Zr-- 1V--1Fe are initially acceptable on the basis of corrosion resistance and strength; however, hydrogen pickup is excessive. The current work is for the study of ternary alloys which are intended to show an optimum combination of corrosion, strength, and hydrogen-pickup properties. (auth).

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.).

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.).