Coupled La2O3 strengthening and HERF-induced hierarchical substructures enable wide-temperature strength-ductility synergy in ODS tungsten

HERF creates hierarchical substructures with 66.3% LAGBs in ODS-W. • La 2 O 3 particles stabilize grain boundaries and impede dislocation motion. • The forged alloy reaches 1204 MPa UTS and 4.9% elongation at 200 °C. • Tensile BDTT is at or below 100 °C, with ductility retained to 600 °C. • CPFEM and TEM reveal continuous slip transfer and broad stress redistribution. Oxide-dispersion-strengthened tungsten (ODS-W) alloys are promising candidates for fusion energy and other extreme environments, yet their application remains limited by low-temperature brittleness, weak strain hardening and grain-boundary cracking. Oxide particles can pin grain boundaries and suppress coarsening, but excessive intergranular enrichment may also promote local stress concentration and intergranular fracture. Here we develop a multiscale microstructure design strategy that combines bottom-up powder synthesis with top-down high-energy-rate forging (HERF). Nanoscale W-1 wt% La 2 O 3 composite powders were prepared by spray drying, carbothermic pre-reduction and hydrogen deep deoxygenation, followed by low-temperature hydrogen sintering. Subsequent HERF reconstructed the W matrix into an elongated hierarchical structure containing dense sub structures and dislocation networks. The characteristic structural size decreased from 2.72 to 0.81 μm, while the fraction of LAGBs increased from 3.8% to 66.3%. The forged alloy showed measurable tensile ductility at 100 °C, indicating a brittle-to-ductile transition temperature (BDTT) below 100 °C. It achieved an ultimate tensile strength of 1204 MPa and a total elongation of 4.9% at 200 °C, while maintaining a favorable strength-ductility balance from 100 to 600 °C. Multiscale characterization combined with DFT, MD and CPFEM simulations shows that La 2 O 3 stabilizes the refined microstructure through grain-boundary pinning, while intragranular particles, forged substructures and dislocation networks promote dislocation storage, plastic-strain transfer and stress redistribution. These coupled effects suppress premature crack initiation and enable wide-temperature strength-ductility synergy in ODS-W. Download: Download high-res image (272KB) Download: Download full-size image