Electric current-driven heterogeneous microstructures in dual-phase titanium alloys.

Heterostructures are a powerful strategy for overcoming the long-standing strength-ductility trade-off in structural materials. However, conventional routes to such architectures often rely on complex thermomechanical treatments, limiting scalability and energy efficiency. Here, we report a hierarchical multiphase heterogeneous microstructure in dual-phase titanium alloys, achieved through a single-step high-density pulsed electric current treatment. The resulting architecture comprises 5-6 phases or components across multi-scale from 1 nm to 10 µm, and exhibits a breakthrough in the strength-ductility trade-off, achieving 13.5% and 12.1% higher strength and 13.1% and 14.5% greater ductility for Ti-6Al-4V and Ti-6Al-7Nb, respectively. In-situ transmission electron microscopy and pre-micromachined structure analysis reveal a previously unreported phase transition mechanism: electron wind-driven precipitation of nanoscale α' martensite within β phases via limited atomic diffusion, accompanied by localized chemical ordering. This work introduces a rapid and energy-efficient processing method, where the entire treatment is completed within milliseconds and the total energy consumption is reduced by more than 50% compared to conventional processing methods. The proposed approach offers a promising route for designing and modifying metallic heterostructures, holding significant implications for next-generation structural materials.