Hydrogen accumulation and distribution during the saturation of a VT1-0 titanium alloy by an electrolytic method and from a gas atmosphere

Abstract

Abstract-The accumulation, distribution, and thermally stimulated release of hydrogen in a VT1 0 tita nium alloy during electrolytic saturation and gas phase saturation are studied. After electrolytic saturation, a 0.4 μm thick surface layer consisting of δ hydrides with a binding energy of 108 kJ/mol forms in the alloy. The hydride dissociation after electrolytic saturation in heating occurs in the temperature range 320-370°C. After saturation from a gas atmosphere, δ hydrides with a binding energy of 102 kJ/mol form throughout the alloy volume. The dissociation of the hydrides formed during gas phase saturation in heating occurs in the temperature range 520-530°C. A further increase in the temperature is accompanied by the transformation of titanium from the α into the β modification. At 690-720°C, the phase transformation is completed, and another hydrogen desorption peak appears in a thermally stimulated hydrogen desorption spectrum.

Specific Features of Deformation of the Nitinol Alloy After Electrolytic Hydrogenation

“…It could be expected that the dependences of fracture stresses and plasticity on the hydrogenation current (opposite to the traditional dependences) are caused by the formation of a very brittle hydride phase on the surface of alloy in the course of electrolytic hydrogenation of the specimen rather than by the hydrogen embrittlement of the martensitic phase, which is sensitive to the content of absorbed hydrogen. Indeed, titanium alloys used for the production of hydrogen storage batteries are characterized by the formation of a hydride phase with the corresponding stoichiometric composition for certain concentrations of hydrogen [20]. Note that the hydrogen concentration in the surface layer of hydride is determined not by the hydrogenation current but by the stoichiometric composition of the formed hydride.…”

Investigation of hydrogenation parameters influence on the hydrogen sorption rate by titanium with nickel layer

“…On the other hand, hydrogen sorption rate depends on the hydrogenation parameters. The main hydrogenation parameters are temperature and pressure in the reaction chamber [3,[14][15][16][17].…”

“…Hydrogen interaction with such materials is actual problem studied for many years. The penetration and accumulation of hydrogen in titanium structural components lead to degradation of physical, mechanical and operational properties caused by hydrogen embrittlement and delayed hydride cracking [3,4].…”