Hybrid Additive Manufacturing of a Ti–6Al–4 V (Electron Beam‐Powder Bed Fusion) and a AISI 316 L (Laser Beam‐Powder Bed Fusion) via Dissimilar Transient Liquid Phase Bonding

Present study investigates a hybrid additive manufacturing strategy using transient liquid phase bonding (TLP) to join a laser beam powder bed–fused AISI 316 L with an electron beam powder bed–fused Ti–6Al–4 V utilizing a copper interlayer. TLP is performed in a vacuum furnace for 1 h at 890, 930, and 970 °C. Joint zones (JZs) are analyzed by scanning electron microscopy and X-ray diffraction; mechanical properties by microhardness and shear tests; corrosion resistance by electrochemical impedance spectroscopy, cyclic potentiodynamic polarization, and immersion in phosphate-buffered saline solution. The findings indicate that raising the bonding temperature to 970 C leads to an expansion of the isothermal solidification region, effectively eliminating Ti–Cu intermetallic compounds at the joint center. However, this temperature also promotes titanium and iron diffusion, resulting in the development of brittle Ti–Fe phases. Consequently, joint hardness increases, while shear strength declines—from 301.6 MPa (TLP 890) to 262 MPa (TLP 930) and 174 MPa (TLP 970). Corrosion resistance rises from an R1 value of 241.5 kΩ cm2 (TLP-890) to 314.4 kΩ cm2 (TLP-970), while corrosion current density (Icorr) decreases from 1.91 × 10−3 μA cm−2 (TLP-890) to 6.55 × 10−4 μA cm2 (TLP-970).