Hierarchical microstructures and strengthening mechanisms of nano-TiC reinforced CoCrFeMnNi high-entropy alloy composites prepared by laser powder bed fusion

•A novel cross-scale hierarchical microstructure is achieved in additively manufactured HEA composites reinforced with nano-scale TiC.•The incorporation of different contents of nano-scale TiC particles into the HEA matrix allows for literally tailoring the morphology of this hierarchically structured microstructure.•The strength and ductility of additively manufactured HEA composites are synergistically improved.•The introduction of nano-scale TiC into the HEA matrix overcomes the strength-ductility trade-off via eliminating the formation of oxide inclusions and exploiting multiple strengthening mechanisms.•Dislocation strengthening contributes most (∼40%) to the improvement of strength of HEA composites due to the severe sluggish diffusion effect and lattice distortion inherent to HEA materials.