Eutectoid phase transformation in U-Mo-X alloys

U-Mo based alloys undergo eutectoid phase transformation where high temperature gamma-U decomposes into alpha-U and U2Mo phases. In the present study, eutectoid decomposition of gamma-U phase into alpha-U and gamma'-U2Mo phases in three U-9 Mo, U-8Mo-1V and U-8Mo-1Zr alloys was examined. By carrying out de-tailed crystallographic analysis of the eutectoidally decomposed products of the U-9Mo alloy, orientation relationships between the parent and product phases were determined. Using the orientation relation-ship, lattice correspondence among the parent and product phases has been worked out. This lattice correspondence has shown that the product lattices could be derived from the (110) planes of the parent gamma-phase wherein the (110) plane of the gamma-phase can be converted into the (001) plane of the alpha-phase and (110) or (103) planes of the gamma'-phase. However, during transformation, occurrence of strains within lattice could be one factor through which the kinetics of the phase transformation or morphology of daughter products could be controlled. Based on this idea, ternary alloy additions with different sizes of the solute atoms (Zr or V) have been carried out. This allowed us to manipulate the strain associated with the transformation which was reflected in terms of changes in the width of product phase lamellae.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the eutectoid decomposition of gamma-U phase into alpha-U and gamma'-U2Mo phases in three U-Mo based alloys. Detailed crystallographic analysis was performed on the decomposed products, revealing orientation relationships and lattice correspondence between parent and product phases. Strains within the lattice were found to play a role in controlling the kinetics of phase transformation and morphology of daughter products. Ternary alloy additions with different sizes of solute atoms allowed manipulation of the strain associated with transformation, resulting in changes in the width of product phase lamellae.