ALLOYS OF ALUMINUM, THORIUM AND URANIUM

Abstract

The Al-rich corner of the ternary alloy system Al-- Th-U has been investigated by thermal and microscopic The creep properties of annealed Zircaloy- 2, Zircaloy3, and 15% cold-worked Zircaloy-2 at elevated temperatures were determined. The metallurgical bond formed between electropolished U and Zr cladding by hydrostatic pressing is being evaluated. Oxidation data are given for Nb and Nb alloys in dry air at various temperatures. A study of the phase relationships which occur between the please delete the above abstract===================== analyses to determine an area of low-melting alloys that could be used as a liquid metal fuel in U/sup 233/ breeder reactors. A phase diagram of this Al-rich corner of the system has been proposed. The data indicate that the binary eutectic valleys from the Al-- U and Al--Th systems meet at a point in the neighborhood of the composition of 76 wt.% Al, 18 wt.% Th, and 6 wt.% U to give a ternary eutectic which solidifies at 630 deg C. Although microstructures indicate two different primary phases as required, a third binary valley leading to this ternary eutectic has not been established. Results of the investigation show that there is a rather wide range of compositions of Umore » and Th in Al, varying from 13 wt% U at zero wt.% Th to zero wt.% U at 25 wt.% Th, that can be maintained in a onephase liquid solution at temperatures even lower than 640 deg C. If a temperature of 650 deg C is the minimum, then an even wider variation in U and Th compositions can be tolerated for a single liquid-phase alloy. (auth)« less