Simultaneously enhancing the strength and ductility of W through heterostructured grains driven by controllable oxide distributions

All long, performance optimization in oxide dispersion-strengthened W alloys has predominantly focused on monolithic oxide regulation, neglecting multi-oxide synergy and grain structure design. This paper breaks away from the traditional homogeneous dispersion strengthening paradigm and constructs heterogeneous grain structure through spatially selective distribution of different oxides, thereby resolving the strength-ductility trade-offs. First, guided by thermodynamic calculations, we systematically evaluate the steady-state characteristics of various oxides in W and then identify oxides suitable for intragranular strengthening (HfO₂) and grain boundary stabilization (La₂O₃). Subsequently, through a composite powder blending strategy, we construct a heterogeneous grain structure in W, where a portion of W grains are strengthened by uniformly dispersed HfO₂ nanoparticles, while the remaining remain relatively soft and dispersoid-free. Compared to conventional W-La₂O₃ alloy, the W-La₂O₃-HfO₂ alloy we developed yields a 33% increase in strength and 57% increase in ductility at 200°C, providing a new direction for fabricating high-performance refractory metals.