Mechanical behavior of Ti-Ta-based surface alloy fabricated on TiNi SMA by pulsed electron-beam melting of film/substrate system

•Additive pulsed e-beam melting of system “(Ti70Ta30) film/NiTi substrate” was used.•Ti-Ta based surface alloy ∼1-μm thick was formed successfully on NiTi substrate.•Nanoindentation and TEM analysis were used for characterization of physical-mechanical properties of Ti-Ta based surface alloy.•Depth-graded multilayer amorphous-nanocrystalline (NC) structure of Ti-Ta based surface alloy is revealed.•NC sublayers have mixed α''(Ti-Ta)-martensite + β(Ti-Ta)-austenite structure.