Bonding of Al-Si and Ti-Ta dissimilar alloys via hot isostatic Pressing: Microstructure and interface stability

This study proposes a three-dimensional diffusion bonding (3D-DB) strategy for achieving metallurgical joining between Al-Si and Ti-Ta alloys with markedly dissimilar physical and mechanical properties. The technique is applicable to the fabrication of geometrically complex tubular components operating under extreme thermomechanical conditions, where conventional welding methods are often inadequate for ensuring structural and thermal reliability. The 3D-DB process employs gas-phase isotropic pressurization at 130 MPa to suppress unidirectional plastic deformation and promote uniform atomic diffusion at the bonding interface, resulting in the formation of a continuous nanoscale diffusion layer. Microstructural analysis reveals that the Al-Si region undergoes significant plastic deformation, primarily attributed to creep and grain boundary sliding, the Ti-Ta region exhibits a stress-induced β to α″ martensitic transformation. Thermal shock testing shows that the joints maintain consistent shear strength after multiple rapid thermal cycles, demonstrating reliable resistance to thermal cycling. These findings suggest that the 3D-DB technique offers a feasible solid-state bonding solution for dissimilar alloy systems and meets the performance requirements for the aerospace industry's demand for high-performance, thin-walled, and structurally intricate components.