Titanium–aluminum (Ti–Al) multi-material structures have tremendous potential for use in lightweight applications. 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, indicating the location-specific properties.

钛-铝 (Ti-Al) 多材料结构在轻量化应用方面具有巨大潜力。激光粉末床融合（LPBF）由于其材料调制的高度灵活性，可以制备多种材料。然而，LPBF 生产的 Ti-Al 复合材料极易发生界面开裂。在这里，我们通过引入铜中间层，以热力学计算为指导，展示了一种在 LPBF 中不润湿钛和铝合金的新型界面焊接方法。Cu中间层有效地阻止了Ti-Al IMC的形成并抑制了界面开裂。通过 LPBF 成功制备了多材料 Ti-6Al-4 V/Al-Cu-Mg (TiA/AlA) 陀螺晶格，并通过实验和计算揭示了它们的变形机制。尤其，TiA 和 AlA 直接键合的多材料 TiA/AlA 晶格遭受由有害的 Ti-Al 化合物引起的严重界面开裂。相比之下，多材料 TiA/Cu/AlA 晶格在界面处无裂纹，并显示出局部剪切断裂模式，其中 AlA 部分首先变形，然后是没有界面坍塌的 TiA 部分，表明特定位置的特性。