Pure plutonium behavior under negative pressures

Dilatometry curves on plutonium show reproducible hysteresis on heating and cooling. Simultaneous electrical resistivity and dilatometric measurements together with the pressure-temperature phase diagram extrapolated to negative pressures provide an understanding for the differences between the heating and cooling curves. Using the extrapolated pressure-temperature phase diagram, this study shows that the internal stresses produced in temperature cycling are much larger than previously thought and that negative pressures (tension) play a significant role in the behavior of plutonium metal. (orig.)