The effect of hydrogen treatment on microstructures evolution and mechanical properties of titanium alloy fabricated by selective laser melting

•Increasing hydrogen content will make β phase stabler.•After solution treatment, α' and α" martensite will coexist in the structure.•After aging, the original microstructure will form fine-grained microstructure.•After dehydrogenation, the β crystal structure becomes finer and the crystal grains appear equiaxed.•Hydrogenation can improve the plastic deformation ability of Ti-6Al-4V titanium alloy.