Formation of porosity in uranium under the action of thermal cycling

In accelerated thermal cycling with a cycle of 50 sec period, considerable changes appear in uranium after 50–1000 cycles, depending upon the temperature range of the cycle. Cycling in the temperature range of the -phase (with heating up to between 550 and 600 °C) produces in texturcd uranium (containing about 0.1% carbon) a directional deformation and porosity, accompanied by a drop in density. After 5000 cycles, the drop in density amounts to 8% Thermal cycling with = ß = -transformations produces a pronounced distortion of the original shape of uranium speclmens and intense porosity formation, with a considerable drop in density, which attains 30% after 1000 cycles.