Formation of Gradient Structures in a Titanium Alloy during Reversible Hydrogen Alloying

Abstract—The possibility of transforming a coarse lamellar structure and creating a gradient structure in titanium alloy VT23 samples during thermohydrogen treatment is investigated. The variation of the concentration–time hydrogenation annealing parameters is shown to control the hydrogen penetration depth and a surface layer structure. Subsequent low-temperature vacuum annealing makes it possible to transform a coarse lamellar structure into a fine structure with a hardness of 40 HRC. The thickness of a layer with a fine structure after unidirectional hydrogenation with a barrier coating is found to be twice as large as that after volumetric nonequilibrium hydrogenation in the absence of the coating.