Comminution of the U-4Zr-6Nb and U-3Zr-9Nb alloys by the hydration and dehydration process

A necessary stage for the fabrication of nuclear fuel plates is the comminution of uranium base alloy with a control of particle size. In this paper, was uses the alloys U-4Zr-2Nb and U-3Zr-9Nb. These alloys retain the gamma phase in a metastable form in a low temperatures and his density are very high. These alloys was thermally treated with different conditions to promote the high temperature gamma phase grain growing followed by a partial decomposition of gamma phase into a alpha phase in the gamma phase grain boundary. This last thermal treatment (partial decomposition) was made in the two-phase region. The hydriding-dehydriding was performed in a Sievert-Type Apparatus, the granulometry was obtained in a Cilas equipment and the products characterization was made by conventional methods of quantitative metallography. This paper shows the influence of thermal treatments on the hydriding kinetics, grain growing and the particle size of the obtained powder. (author)