Temperature de recristallisation de l'uranium de fusion de zone

Measurements of the rati o of the resistance of zonemelted U samples of 293 c- K to that at 78 c- K, of the polycrystalline microhardness of the samples, of the x-ray scattering by the samples, and of the surface details of the samples under polarized light are carried out. These measurements are used to calculate the recrystallization temperature of the zone- melted U (namely, 270 c- C), and to show that a pronounced grain growth takes place during the zone melting of electrolytic-purity U. (T.F.H.)