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Journal of Alloys and Compounds, Volume 586, 15 February 2014, Pages 709-717.
Michael Ling, Roderick F.E. Jenkins, Nigel Park.
AWE, Aldermaston, Reading RG7 4PR, UK.
Abstract
The effects of Ga concentration and starting condition of Pu–Ga alloys on their solid-state phase transformation behaviours in a set of Pu–Ga alloys containing 0.18–0.63 wt.% Ga were studied under non-equilibrium conditions with a heating/cooling rate of 10 °C/min in the temperature range of 25–560 °C by a dilatometry method. The characteristic abrupt slope changes shown in the dilatometry tracks during heating and cooling are ascribed to the known phase transformations in the Pu–Ga alloys. The rationale for such an ascription is discussed. The study showed that, as expected, Ga concentration and the starting condition of the Pu–Ga alloy have significant effects, demonstrated by the variety of the onset and completion temperatures of a phase transformation. We find that the nature of as cast {Alpha}-phase is independent of the nominal Ga content. The ε → {Delta} transformation happens through two mechanisms when Ga < 0.63 wt.%. Furthermore, the increase of thermal expansion coefficient of {Delta}-phase with increasing Ga is also confirmed.
Additional information:
The authors extend thanks to all members of staff in AWE’s plutonium R&D laboratory for their help in the preparation and characterisation of these alloys.
