Cell boundary engineering of ferrous medium-entropy alloy fabricated by laser powder bed fusion

The concept of cell boundary (CB) engineering was proposed to explore the potential benefits of segregation engineering in obtaining superior mechanical properties in materials printed via laser powder bed fusion (LPBF). Mo-doped and Mo-free ferrous medium-entropy alloys (FeMEAs) were additively manufactured using LPBF. A high density of dislocation networks with Mo segregation along the CB was observed in the Mo-doped FeMEA. The Mo-doped FeMEA achieved significantly enhanced strength and ductility compared to the Mo-free counterpart. This strengthening effect was attributed to the higher contribution of back stress and improved strain hardening ability, facilitated by the Mo segregation and nano-precipitates at the CBs. This work presents a guideline for alloying design in additive manufacturing, aiming to produce high-quality products with excellent mechanical performance by utilizing the unique segregation engineering of LPBF-driven microstructures.