Revisiting the Zr–Al system for next-generation nuclear applications

Zirconium alloys are commonly used as cladding materials for light-water reactors, but their strengthening mechanisms degrade at the higher temperatures proposed for next-generation fission and fusion reactors. This review reassesses the Zr–Al system as a potential candidate structural material for next-generation non-aqueous reactor environments. Aluminium offers potent solid-solution and precipitate strengthening, raises the α → β transition temperature, and maintains a low thermal neutron absorption cross-section, addressing key limitations of current Zr–Sn and Zr–Nb alloys. Historical concerns over aqueous breakaway oxidation are re-evaluated in the context of Generation IV coolants, finding that the coolant compatibility of Zr–Al may be microstructure-dependent. As such, Al-bearing Zr alloys warrant consideration for some next-generation nuclear applications.