An investigation of structural changes caused by neutron irradiation of a uranium molybdenum alloy

Abstract Specimens of an alloy containing 9 wt per cent of molybdenum were irradiated. The electrical resistance was measured and the structure examined by X-ray diffraction and metallographic techniques. The specimens were prepared by suitable heat treatment to have eutectoid α + γ′ structures with various degrees of dispersion. It was established that the rate of homogenization of these two-phase structures during irradiation was inversely proportional to the square of the thickness of the laminae in the eutectoid. In the homogeneous γ-phase changes in structure and properties under irradiation are essentially complete in 2–4 hr. The ordered γ′-phase was found to be disordered after a few hours of exposure to neutrons. All these phenomena can be adequately explained on the basis of the theory already published. (2) However the size of the thermal spike and the energy dissipated were found to be smaller than determined previously and were 2·5 × 10 −17 cm 3 and 2 MeV respectively.