Spinodal decomposition and oxide dispersion-mediated multi-architectured heterostructure facilitating fine-grained W-based composite strength–ductility synergy

Tungsten heavy alloys (WHAs) designed via ductile-phase toughening strategies show promise in overcoming the intrinsic brittleness of W, enabling broad applications. However, as application scenarios demand increasingly stringent properties, achieving strength–ductility synergy has become an urgent challenge. In the present work, novel fine-grained (92- x )W–4.9Ni–2.1Fe– x Sn–1Y 2 O 3 ( x = 0, 0.125 wt.%, 0.25wt.%, 0.5wt.%, 1 wt.%) composites were developed through microalloying with low-melting-point Sn and the incorporation of Y 2 O 3 second-phase particles. Significant grain refinement of W grains was achieved in the composite, accompanied by the formation of Sn-rich and Sn-depleted regions in the binder phase through spinodal decomposition. Moreover, Y 2 O 3 particles are uniformly dispersed within the grains and along grain boundaries. The sample with 0.25 wt.% Sn exhibited an optimal combination of tensile strength (1077 MPa) and elongation (30.1%). The exceptional properties arise from synergistic mechanisms: the addition of Sn significantly lowers the liquid-phase sintering temperature, dropping from ~ 1500 to 1300 ℃, while Y 2 O 3 particles exert a pinning effect, promoting rapid densification and pronounced refinement of W grains (only 6.56 ± 0.31 μm). In addition, spinodal decomposition creates a rugged chemical landscape, coupled with abundant interfaces from Y 2 O 3 particles, establishing high heterogeneous deformation-induced stresses. The long-range internal stresses enhance twin activation and dislocation interactions in the binder phase, significantly improving strain-hardening capacity. Meanwhile, enhanced interfacial load transfer promotes obvious plastic deformation in W grains via the formation of incidental dislocation boundaries and geometrically necessary boundaries. These findings open new avenues for a deeper understanding of the deformation behavior of biphasic composites, rendering this material design strategy a promising approach for achieving strength–ductility synergy across various alloy systems. Graphical abstract The alternative text for this image may have been generated using AI.