Characterization of Ni–Ti Alloy Powders for Use in Additive Manufacturing

Additive manufacturing (AM) offers a fully integrated fabrication solution within many engineering applications. Particularly, it provides attractive processing alternatives for nickel-titanium (Ni–Ti) alloys to overcome traditional manufacturing challenges through layer by layer approach. Among powder-based additive manufacturing processes, the laser beam melting (LBM) and the electron beam melting (EBM) are two promising manufacturing methods for Ni–Ti shape memory alloys. In these methods, the physical characteristics of the powder used as raw material in the process have a significant effect on the powder transformation, deposition, and powder-beam interaction. Thus, the final manufactured material properties are highly affected by the properties of the powder particles. In this study, the Ni−Ti powder characteristics are investigated in terms of particle size, density, distribution and chemical properties using EDS, OM, and SEM analyses in order to determine their compatibility in the EBM process. The solidification microstructure, and after built microstructure are also examined for the gas atomized Ni–Ti powders.