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초록

Creating high-strength metals is essential for resource conservation and enhancing energy efficiency. Nevertheless, the pursuit of achieving both high strength and ductility in metals continues to present a significant challenge. In this study, we introduced a method aimed at achieving improved strength-ductility synergy in metallic materials. Micro-laminated duplex stainless steel (DSS) matrix composites were developed by employing the laser powder bed fusion (LPBF) technique, resulting in four distinct heterogeneous structures. 316 L austenitic stainless steel (ASS) and 2507 DSS powders, together with micron-sized TiC particles, were utilized to create microscale layers of austenite and ferrite. Austenite layers with bimodal grains and ferrite layers with fine grains were alternately formed. In-situ formed TiCxNy nanoparticles were found in these layers, and duplex grains were produced in and near ferrite layers. Owing to these heterogeneous structures, the micro-laminated composites had high ultimate tensile strength (∼1.06 GPa) and uniform elongation (∼21.9 %), showing enhanced strength-ductility synergy compared to other reported heat-treated LPBF-fabricated 2205/2507 DSSs. Particularly, the strong hetero-deformation induced (HDI) stress was found to be formed by these heterogeneous structures, facilitating the enhancement of strength-ductility synergy. Interestingly, the micro-laminated composites achieved favorable isotropic tensile properties due to the alternate stacking of austenite and ferrite layers, and the recyclability of unused powder was well demonstrated. This study can offer an advanced manufacturing approach for metals in various industrial applications. © 2025 Elsevier B.V.

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