A strong and ductile medium-entropy alloy with a thermally stable cellular heterostructure by additive manufacturing

• The thermodynamics-based design of a high thermal stability medium-entropy alloy is achieved. • Segregation of Ti and Ta at cell boundaries forms the cellular heterostructure. • Cell-boundary γ’ clusters impede dislocation motion, while inter-cluster gaps allow uniform slip across the cellular structure. • Superior tensile properties are attributed to back stress and precipitate strengthening.