Building core–shell heterostructure in Ni₃₆Co₃₀Cr₁₁Fe₁₁Al₉Ta₃ high-entropy alloy for overcoming strength-ductility trade-off via ultrasonic solidification

Ultrasonic solidification successfully constructed an exceptional core–shell heterostructure in Ni₃₆Co₃₀Cr₁₁Fe₁₁Al₉Ta₃ alloy, featured by tiny Laves particles distributing along grain boundaries of equiaxed γ phase. Transient cavitation refined primary γ phase, transforming coarse dendrites into equiaxed grains. Acoustic streaming accelerated solute depletion during γ growth, leaving more Ta atoms in the residual liquid among grain boundaries, where abundant Laves particles discontinuously nucleated and grew by the aid of stable cavitation. This core–shell heterostructure exhibited remarkable HDI strengthening and further activated stacking-fault networks and high-density L-C locks during deformation, resulting in 34% increase in ultimate strength to 1202 MPa without ductility sacrifice.