Quantitative method for describing heterogeneity in plutonium-gallium alloys

Abstract

A new method for describing gallium (Ga) heterogeneity in plutonium–gallium (Pu–Ga) alloys in terms of two parameters, d_x and m₀, is presented in this paper. The parameters are derived from a modified Boltzmann function. The resulting sigmoidal curve function is fitted to a grain radius bearing curve, derived from quantitative Ga distribution map data. Describing the heterogeneity in terms of the derived parameters enables the effect of different parameters on the rate of homogenisation of the Ga to be quantitatively characterised. This quantification will allow us to determine the relationships that material properties and heat treatment conditions have on the rate of homogenisation of the Ga. Preliminary results presented here indicate a strong log–log correlation between the heat treatment time at a given temperature and the resulting heterogeneity, and also indicates that the combined iron (Fe) and nickel (Ni) content in the alloy affects the homogenisation rate.