Plutonium-Gallium Alloy

High Quality Content by WIKIPEDIA articles! The plutonium-gallium alloy (Pu-Ga) is an alloy of plutonium and gallium, used in nuclear weapon pits. To stabilize plutonium in its less dense and more machinable phase, it is alloyed with 3-3.5 mol.% (0.8-1 wt.%) gallium. This alloy was developed during the Manhattan Project, and is used in nuclear weapon pits since then. Under pressure of hundreds gigapascals the stabilized phase transforms to more dense phase. As even the phase is thermodynamically unstable, there are concerns about its aging behavior. Due to very large difference of density (and therefore volume) of the phases, and the very low temperature of 115 C of the - transition temperature which can be too easily reached during the service life of the pit, prevention of the phase transition and the associated mechanical deformations and consequent structural damage and/or loss of symmetry is of critical importance.