Resistive thermal fusion interface: A novel additive manufacturing process of titanium alloy

Additive manufacturing of titanium alloy has promoted their wider application in the aerospace and automotive industries. However, safety, cost and forming quality pose serious challenges to existing additive manufacturing technologies. Additionally, complete melting and rapid cooling inhibit the gas from escaping in the melt pool during solidification, leading to the presence of pores inside the sample, which deteriorates the properties of components. Herein, a novel additive manufacturing process of resistive thermal fusion interface with low cost is presented. The contact resistance heat is generated when the current passes through the contact interface between metal wires, which causes the interface to fuse while the rest part of material remains solid. This novel additive manufacturing process was employed to fabricate Ti-5Al-2.5Sn Ti-alloy components in this work. The macrostructure, defects feature, grain structure, tensile properties of the additively manufactured samples with different currents were analyzed systematically. The results reveal that, components without pore defects are obtained by selecting appropriate parameters. Samples possess strength-ductility synergy (yield strength of 864 ± 7 MPa, ultimate tensile strength of 896 ± 4 MPa and elongation of 17.7 ± 1.11 %), which is similar to samples fabricated by L-PBF with annealing treatment. Besides, the mechanisms of resistive thermal fusion interface as well as the microstructure–mechanical property relationships were elucidated in detail. Therefore, this work provides a promising way to fabricate high performance titanium alloy.