No directional effects were observed in annealed zirconium when creeps tested at 500 F. Increasing the stress from 10,000 to 16,000 psi increased the total deformation at 2000 hours from 0.31 to 5.7 per cent and the secondary creep rate from 0. 3 x 10 -4 per cent per hour to 3.0 x 10 -4 per cent per hour. For the zirconium - 3.66 per cent uranium alloy, the effect of increasing the stress from 20,000 psi to 30,000 psi was to increase total de formation at 2000 hours from 0.39 per cent to 5.25 per cent, whereas the secondary creep rate increased from 7 x 10~° per cent per hour at 20, 000 psi to 10 x 10_6per cent per hour at 22, 000 psi. Above 22,000 psi, the creep rate was nil.
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