Synergistic improvement of strength and ductility in additively manufactured in-situ phase-transitioned dual-phase hetero-structures

Laser powder bed fusion additive manufacturing offers unique advantages for constructing dual-phase heterogeneous structural materials. This study employed mechanically mixed powders to successfully fabricate dual-phase heterogeneous alloys exhibiting both high strength and ductility through an in-situ phase transformation strategy. Through combined numerical simulations and experimental characterization, the formation mechanism and evolution patterns of the in situ dual-phase heterogeneous microstructure were systematically elucidated. Crystal plasticity finite element analysis further revealed that the heterogenous deformation-induced strengthening effect constitutes the core mechanism for achieving synergistic enhancement of strength and toughness. This in-situ dual-phase design strategy opens new avenues for developing high-performance metallic materials.