The relationship between gamma and delta hydrides in zirconium-hydrogen alloys of low hydrogen concentration

摘要: Abstract The stability of the γ-hydrides and possible existence a δ-hydride → γ-hydride transformation has been studied in sponge zirconium sheet containing up to 500 ppm hydrogen (4.33 at %) temperatures range 150–250°C. Ageing quenched specimens which initially contained only resulted replacement this phase by δ-hydrides rate was dependent on temperature, while ageing furnace-cooled specimen, did not result change type hydrides present. Evidence obtained showed that could involve an in-situ transformation. results support view is metastable transition precipitate equilibrium phase.