| Abstract Scope |
Achieving high tensile ductility is crucial in structural metals, supporting reliable load-bearing performance and good formability. Recently, heterostructured materials (HMs) have been reported to show superior tensile properties that surpass their homogenous counterparts. However, the underlying mechanisms for HMs with mesoscale heterogeneities, i.e., in the length scale of a few hundreds of micrometers, are overlooked. Recent advances in additive manufacturing (AM) have provided opportunities to fabricate HMs over the mesoscale range with structural complexity. In this work, we employ the AM method to fabricate bi-metallic heterostructured steels (HSs). We achieved 27.3%, 11.5%, and 1.8% improvements in the tensile ductility, ultimate tensile strength, and yield strength over 316L, respectively. Such enhanced tensile properties are mainly attributed to 1. A new confined-necking co-deformation, offering more work hardening to the whole sample; 2. Switching between necking-induced and shear-induced failure modes; and 3. HDI hardening effect. |