Additive manufacturing of Ti-6Al-4V/Al-Cu-Mg multi-material structures with a Cu interlayer

摘要

Titanium-aluminum (Ti-Al) multi-material structures have tremendous potential for use in lightweight appli-cations. Laser powder-bed fusion (LPBF) enables the preparation of multi materials owing to its high flexibility of material modulation. However, LPBF-produced Ti-Al multi-materials are highly susceptible to interface cracking. Here, we demonstrated a novel interface welding method of unwetting titanium and aluminum alloys in LPBF by introducing a copper interlayer, which is guided by thermodynamic calculations. The Cu interlayer effectively prevented the formation of Ti-Al IMCs and suppressed interface cracking. Multi-material Ti-6Al-4 V/ Al-Cu-Mg (TiA/AlA) gyroid lattices were successfully prepared via LPBF and their deformation mechanisms were revealed both experimentally and computationally. Notably, multi-material TiA/AlA lattices where TiA and AlA were directly bonded suffered from severe interface cracking caused by detrimental Ti-Al compounds. By comparison, multi-material TiA/Cu/AlA lattices were crack-free at the interface and showed a local shear fracture mode where AlA portion deforms first, followed by the TiA portion without interfacial collapse, indi-cating the location-specific properties.

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