[3] It has been put forward as a structural material for the casings of the physics package in nuclear weapons, including those of North Korea.
[6][7] Binary alloy compositions were first studied to avoid the mechanical problems of pure uranium: corrosion, dimensional instability, inability to improve its mechanical properties by heat treatment.
Uranium-niobium-zirconium was found to be corrosion resistant and to permit age hardening, which could increase its hardness from 760 to 1,860 megapascals (110 to 270 ksi).
Further aging produces a monoclinic ɑ″ phase that is observed metallographically as a Widmanstätten pattern.
[14] Early studies were uncertain as to whether these were inherent behaviours, or artifacts of their processing.