Laser additive manufacturing of bimetallic structure from Ti-6Al-4V to Ti-48Al-2Cr-2Nb via vanadium interlayer.

• Using the V interlayer, a metallurgical defect-free TiAl/TC4 BS has been successfully fabricated by LAM technology. • The V interlayer was very effective in reducing the formation of brittle α 2 phase in the TiAl/TC4 BS. • Tensile results showed that the V interlayer is an effective joining method for TC4/TiAl BS. As a potential candidate material, Ti6Al4V (TC4)/Ti48Al2Cr2Nb (TiAl) bimetallic structure (BS) material has a good development prospects in the field of aerospace engineering, and has a broad application prospects for the integrated manufacture of aero-engine turbine blades (TiAl) and turbine disks (TC4). However, via the direct bonding of TC4/TiAl BS, it is easy to produce brittle intermetallic compounds which increases the crack sensitivity. Therefore, to a certain extent, the application of TC4/TiAl BS is limited. In this study, we use laser additive manufacturing (LAM) technology to prepare the TC4/TiAl BS via a V interlayer, which further limits the formation of a brittle phase. The experimental results show that the V interlayer can effectively limit the formation of the brittle phase (Ti 3 Al), which reduces the crack sensitivity of the formed parts, and forms a good metallurgical joint at the TC4/TiAl BS interfaces. Results of room temperature tensile tests reveal that the tensile strength and elongation of the BS specimens are ~476 MPa, and ~2.8% respectively, which means that the strength of the joint exceeded that of the deposited TiAl alloy without the V interlayer. [ABSTRACT FROM AUTHOR]