Enhancing strength-ductility synergy in an ex situ Zr-based metallic glass composite via nanocrystal formation within high-entropy alloy particles

•A strategy for designing ductile metallic glass composites by forming nanocrystals in the high-entropy alloy particles during deformation was proposed.•The ex situ high-entropy alloy particle toughened Zr-based metallic glass composites were prepared by spark plasma sintering.•By adding CoCrFeNiAl high-entropy alloy particles, the Zr-based metallic glass composites exhibit enhanced strength-ductility synergy.•The toughening mechanisms were discussed in accordance with experiments and modeling.