Search

The paper investigates the effect of hydrogenation towards the concentration of 0.33 wt % on the structural and phase state and the deformation process development during tension of the ultrafine-grained Zr–1 wt % Nb alloy (hereinafter Zr-1Nb) at the temperature range of 293–973 K. Hydrogen presence in the alloy in solid solution and hydride precipitates are found that results in an increase of its strength and plastic characteristics at room temperature. At elevated temperatures hydride dissolution activates dislocation motion that leads to strength characteristics reduction and to rise of deformation-to-failure.

Investigation of hydrogen accumulation and distribution in zirconium alloy Zr1Nb after electrochemical and gas-phase hydrogenation was carried out. The hydride rim with sufficient thickness could not be obtained by electrolytic saturation. The hydrogen sorption rates of zirconium alloy at different temperatures were calculated: 1.65 × 10−4 wt %/min at 350°C, 2.4 × 10−2 wt %/min at 450°C, 7.3 × 10−2 wt %/min at 550°C. The decrease of cooling rate from 10 to 2°C/min after gas-phase hydrogenation lead to increased thickness of the hydride layer from 50 to 59 µm.

Influence of gas-phase hydrogenation temperature and cooling rate on defect structure of commercially pure titanium alloy was experimentally studied by means of positron annihilation spectroscopy. The change of temperature in the process of gas-phase hydrogenation was in the range of 500–700°C, while the change of cooling rate was in the range of 0.4–10.4°C/min. With increasing of gas-phase hydrogenation temperature, significant increase of hydrogen sorption rate was found. High temperature gas-phase hydrogenation of commercially pure titanium alloy lead to the formation of vacancy and hydrogen-vacancy complexes. For the same concentration of hydrogen, temperature variation or variation of cooling rate had no effect on the type of defect. However, this variation provides significant changes in defect concentration.