BLT-Ti65, a multi-component near-alpha high-temperature titanium alloy, stands out for its remarkable ability to maintain exceptional strength, ductility, creep resistance, corrosion resistance, and thermal stability at temperatures up to 650°C. This far surpasses the operational temperature limits of traditional high-temperature titanium alloys, making it a highly sought-after material in aerospace, chemical equipment, marine engineering, and other high-performance applications.
However, the additive manufacturing process of Ti65 powder often encounters challenges such as porosity and cracks, arising from unfused, partially melted powder particles, and interlayer/track delamination. These defects, acting as stress concentrators, significantly increase the risk of material failure, potentially leading to fractures and adversely affecting the performance of the formed components. To address this issue, the powder research and development engineers at Bolytech have relentlessly pursued technological advancements, introducing BLT-Ti65 powder specifically tailored for Selective Laser Melting (SLM) and Directed Energy Deposition (DED).
The nominal chemical composition of BLT-Ti65 powder is Ti-5.9Al-4Sn-3.5Zr-0.3Mo-0.4Si-0.3Nb-2.0Ta-1.0W-0.05C, with particle sizes ranging from 15-53μm (suitable for SLM processes) and 75-180μm (suitable for DED processes). After heat treatment, components produced using 15-53μm BLT-Ti65 powder exhibit yield strengths of 483-503Mpa, tensile strengths of 604-624Mpa, and elongation rates of 16.5%-26.5% at 650°C. Similarly, components made with 75-180μm powder demonstrate yield strengths of 478-538Mpa, tensile strengths of 588-648Mpa, and elongation rates of 22%-32% under the same temperature conditions. Bolytech has showcased its SLM forming capabilities by successfully producing a cabin wing demonstrator using 15-53μm BLT-Ti65 material, featuring a dense and defect-free structure typical of integrated cabin wing manufacturing.
Bolytech has overcome significant hurdles related to cracking, deformation control, and printing process management in BLT-Ti65, developing viable forming processes and parameters that are now compatible with all Bolytech's equipment models.
China's research into high-temperature titanium alloys, particularly those suitable for additive manufacturing, is still in its infancy. Through the optimization of Ti65's composition, forming process parameters, and process control, Bolytech has successfully developed and validated BLT-Ti65, opening up new possibilities for the application of high-temperature titanium alloys in high-temperature components of aero-engines, scientific experiments involving novel materials and structures, and beyond.
