ISSN 3041-1815. Physicochemical Mechanics of Materials. 2026.
Volume 62, Issue 4
Kinetics of gas nitriding and phase transformations in additively manufactured Ti6Al4V titanium alloy
Pohrelyuk I. M. 
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Lavrys S. M.
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Tkachuk O. V.
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Kovalchuk I. V.
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Keywords
Ti6Al4V titanium alloy, additive manufacturing, selective laser melting, gas nitriding, diffusion kinetics, activation energy, lattice parameter, phase composition, titanium nitrides, α’ martensite, (α’+α)(N) phase composition.
Cite as
Pohrelyuk I. M., Lavrys S. M., Tkachuk O. V., and Kovalchuk I. V. Kinetics of gas nitriding and phase transformations in additively manufactured Ti6Al4V titanium alloy. Physicochemical Mechanics of Materials. 2026. 62(4), 41-50.
Abstract
The kinetics and phase transformations during gas nitriding (750–850°C) of additively manufactured Ti6Al4V alloy were investigated. The process follows a parabolic law with an activation energy of Eα = 112 kJ/mol. The formation of a gradient layer with a complex phase composition TiN + Ti2N + (α’+α)(N), was revealed. A non-monotonic character of the matrix lattice parameter variation was determined: the diffusion-driven expansion (up to 10 h) changes due to a decrease in the parameters due to nitrogen depletion of the solid solution in favor of nitride growth and nitrogen accumulation by the martensitic phase.