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Additively manufactured hierarchical stainless steels with high strength and ductility

TitleAdditively manufactured hierarchical stainless steels with high strength and ductility
Publication TypeJournal Article
Year of Publication2018
AuthorsWang, YM, Voisin, T, McKeown, JT, Ye, JC, Calta, NP, Li, Z, Zeng, Z, Zhang, Y, Chen, W, Roehling, TT, Ott, RT, Santala, MK, Depond, PJ, Matthews, MJ, Hamza, AV, Zhu, T
JournalNature Materials
Date Published01
Type of ArticleArticle
ISBN Number1476-1122
Accession NumberWOS:000422790000017
Keywords316l, chemistry, corrosion-resistance, deformation, internal-stresses, laser, Materials Science, mechanical-properties, Microstructure, physics, plasticity, powder-bed fusion, properties, tensile

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.

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Structures and Dynamics