Structure and mechanical properties of Ce-La alloys containing 3-10 wt. % La

This paper describes a study of the microstructure and mechanical properties of a range of cerium lanthanum (Ce-La) alloys with La contents of between 3 wt. % and 10 wt. %. Ce-La alloys are regarded as non-radioactive surrogates for delta-phase plutonium (delta-Pu) alloys. The Ce-La alloys were characterised using optical microscopy, energy dispersive spectroscopy and X-ray diffraction while the mechanical properties were determined using micro-hardness, ultrasonic velocity and nanoindentation measurements. The presence of La appears to impart a degree of solid solution hardening to the alloys, as indicated by the modest increase in micro-hardness with increasing La content; a small increase in elastic modulus with La content was also seen. The hardness and elastic modulus values of the Ce-La alloys in this study are similar to those of homogenized Pu-Ga alloys in the Ga-lean part of the delta-Pu phase field. Despite the propensity of the Ce-La alloys to undergo oxidation in air, the oxide thicknesses of the alloys, which were determined by energy dispersive spectroscopy, were found to be insufficient to exert a significant influence on the nanoindentation measurements. Crown Copyright (C) 2020 Published by Elsevier B.V. All rights reserved.

Automated summary

Ce-La alloys exhibit solid solution hardening with increasing La content, resulting in higher hardness and elastic modulus values. Despite being prone to oxidation, the oxide layers on the alloys do not significantly affect nanoindentation measurements.