Characterization of microstructural, mechanical and thermal properties and ageing study of Th-3Â wt.% U alloy

This paper aims at filling the gap in research on Th-U alloys and addresses microstructural, mechanical, thermo-physical and ageing aspects of Th-3 wt.% U alloy. Th-3 wt.% U alloy has a coarse grained (∼100 μm) microstructure having finely dispersed precipitates (∼70 nm) of uranium. Ageing (550-750 °C) behaviour indicates fast solute diffusion kinetics and no remarkable grain coarsening even at prolonged holding at high (1000 °C) temperature. Thermal expansion behaviour of this alloy [CTE(28-670 °C)=11.69 × 10−06 °C−1] is found superior to those of metallic fuels and quite comparable with those of oxide and carbide fuels. Room temperature thermal conductivity of this alloy (35.6 W m−1 °C−1) is ∼1.3 and ∼4.1 times higher than those of uranium and UO2, respectively.