Mechanical Behavior of Alpha, Beta, and Gamma Plutonium

AbstractPlutonium is a highly unusual metal displaying six allotropic phases between room temperature and 550 Centigrade. The crystal structures present vary from low-density high-symmetry cubic phases to high-density low-symmetry monoclinic phases, presenting unique challenges and opportunities for the researcher. In addition, the properties of plutonium may change over time due to radioactive decay, introducing radiation damage and causing changes in chemistry.Castings of high-density Plutonium were created as part of a research and development effort at Los Alamos National Laboratory. The as-cast material was characterized using a variety of techniques, including resonant ultrasound spectroscopy (RUS), dilatometry, and quasi-static mechanical testing. A brief overview of the experimental technique of RUS as it applies to plutonium will be presented, along with discussion of the elastic moduli of alpha plutonium measured in the newly as-cast state. Compression tests of alpha plutonium and tensile tests of beta and gamma phase plutonium will be presented and compared with previous literature and experiments including older alpha plutonium specimens by previous authors