Microstructure evolution and mechanical performance of diffusion-bonded Ti-6.5Al–2Zr–1Mo–1V alloy components fabricated by preform hot isostatic pressing

Ti-6.5Al–2Zr–1Mo–1V (TA15) is a lightweight and heat-resistant titanium alloy increasingly adopted for aerospace structures. Conventional routes for manufacturing complex TA15 components, however, often suffer from high material wastage and low processing efficiency. To overcome these limitations, we employed a hot isostatic pressing diffusion-bonding (HIP-DB) strategy that integrates preform part with powder to produce near-net-shape parts. This study systematically investigates the evolution of microstructure, tensile properties at room-temperature, high-temperature endurance, and fatigue performance of fabricated parts at various processing temperatures. Results indicate that specimens processed at 950 °C exhibit excellent performance associated with a trimodal microstructure, namely with a tensile strength of about 1050 MPa, elongation of about 22.5 %, endurance times of about 170h, and fatigue life of about 6.2 × 10 5 cycles at 700 MPa for powder, solid, and interface regions. Compared with the specimens fabricated at 930 °C, the tensile strength and elongation of specimen fabricated at 950 ° C increased by about 20 % and 10 %, respectively, while that for endurance life and fatigue life at 700 MPa increased about 5 and 6.2 times, respectively. Enhanced interfacial bonding, comparable grain sizes across the interface, and effective crack propagation barriers contribute to the observed improvements in endurance and fatigue resistance of the interface regions. The findings provide valuable insights into the advanced manufacturing of high-performance, complex-shaped TA15 alloy components for aerospace fields.