Determination of elastic moduli at high temperatures for uranium-vanadium alloy and pure plutonium by an ultrasonic method

摘要

Using a contact delay-line ultrasonic device, we measured the elastic properties particularly the shear modulus mu of pure plutonium and uranium-vanadium alloy from ambient temperature to 900 K. Several allotropes of these materials have been detected in the explored temperature range. For plutonium metal, measurements reveal a collapse of mu (T) of about 50 percent for the alpha - > beta phase change and a small increase of 0.2 percent for the beta - > gamma phase change. For uranium-vanadium alloy, we observe a monotonic decrease of about 50 percent of mu (T) for the alpha - > beta phase change. In order to include the phase transition to describe the variation of mu (T), a model has been proposed and applied.