To simultaneously enhance the strength−plasticity synergy and resistance to hydrogen embrittlement(HE),the post-annealing treatment was conducted in a laser powder-bed fusion Ti−6Al−4V alloy to introduce reversible tr...To simultaneously enhance the strength−plasticity synergy and resistance to hydrogen embrittlement(HE),the post-annealing treatment was conducted in a laser powder-bed fusion Ti−6Al−4V alloy to introduce reversible transformation.The microstructure,mechanical properties,and HE behavior of the alloy were analyzed by electron back-scattered diffraction,transmission electron microscopy,slow-strain-rate tensile test,hydrogen permeation and thermal desorption spectroscopy.The as-printed sample exhibited high strength but limited elongation and high HE sensitivity.When annealed at 550℃,the elongation was improved but the hydrogen diffusion rate also increased,thus promoting the formation of brittle hydride.When annealed at 750℃,the reversible transformationα'→β→α'occurred and anα'/β/α'sandwich structure formed,thereby enhancing HE resistance(reducing the total elongation loss to 12%)while maintaining high strength(~1116 MPa).The introduction of nanoscaleβ-phase and soft-orientedα'grain significantly inhibited hydride formation and hydrogen-induced crack propagation.展开更多
基金the National Natural Science Foundation of China(No.52001213)the“Chen Guang”Project(No.20CG65)supported by the Shanghai Municipal Education Commission,China.
文摘To simultaneously enhance the strength−plasticity synergy and resistance to hydrogen embrittlement(HE),the post-annealing treatment was conducted in a laser powder-bed fusion Ti−6Al−4V alloy to introduce reversible transformation.The microstructure,mechanical properties,and HE behavior of the alloy were analyzed by electron back-scattered diffraction,transmission electron microscopy,slow-strain-rate tensile test,hydrogen permeation and thermal desorption spectroscopy.The as-printed sample exhibited high strength but limited elongation and high HE sensitivity.When annealed at 550℃,the elongation was improved but the hydrogen diffusion rate also increased,thus promoting the formation of brittle hydride.When annealed at 750℃,the reversible transformationα'→β→α'occurred and anα'/β/α'sandwich structure formed,thereby enhancing HE resistance(reducing the total elongation loss to 12%)while maintaining high strength(~1116 MPa).The introduction of nanoscaleβ-phase and soft-orientedα'grain significantly inhibited hydride formation and hydrogen-induced crack propagation.
