Abstracts and Available Papers Presented at the
2002 International RERTR Meeting

U-Mo ALLOY POWDER OBTAINED THROUGH SELECTIVE HYDRIDING:  PARTICLE SIZE CONTROL

S.N. Balart, P. Bruzzoni y M.S. Granovsky.

CNEA, Departamento Materiales

Av. del Libertador 8250, 1429 Buenos Aires, Argentina.

ABSTRACT

Hydride-dehydride methods to obtain U-Mo alloy powder for high-density fuel elements have been successfully tested by different authors.  One of these methods is the selective hydriding of the a phase (HSa).

In the HSa method, a key step is the partial decomposition of the g phase(retained by quenching) to a phase and an enriched g phase or U₂Mo.  This transformation starts mainly at grain boundaries.  Subsequent hydrogenation of this material leads to selective hydriding of the a phase, embrittlement and intergranular fracture.  According to this picture, the particle size of the final product should be related to the g grain size of the starting alloy.

The feasibility of controlling the particle size of the product by changing the g grain size of the starting alloy is currently investigated.  In this work an U-7 wt% Mo alloy was subjected to various heat treatments in order to obtain different grain sizes.  The results on the powder particle size distribution after applying the HSa method to these samples show that there is a strong correlation between the original g grain size and the particle size distribution of the powder.

---

---