Effect of hydrogen treatment on properties and structure development in Zr-2.5Nb alloy

Flow stresses at 600 °C of the annealed and quenched Zr-2.5Nb alloy with hydrogen content varying from 0.2 to 20 at%, and microstructure development of the alloy after deformation and subsequent vacuum annealing at 580 °C were studied. It was found that increase in the volume fraction of the βZr-phase due to hydrogen alloying resulted in substantial decrease in the flow stresses and led to αZr-grain/subgrain refinement to submicron level during the deformation at 600 °C. Vacuum annealing resulted in decrease of the hydrogen content and was accompanied by αZr-grain growth.