Hierarchical microstructure and strengthening mechanisms of a CoCrFeNiMn high entropy alloy additively manufactured by selective laser melting

By Z. G. Zhu, Q. Nguyen, F. L. Ng, X. An, Xiaozhou Liao, P. K. Liaw, S. Nai, Jun Wei. Scripta Materialia, 2018

555 citations recorded by the source corpus.

Abstract A near-fully dense CoCrFeNiMn high entropy alloy was additively manufactured by selective laser melting successfully. The as-built samples exhibit a hierarchical structure, including melt pools, columnar grains, sub-micron cellular structures, and dislocations. An outstanding combination of high strength and excellent ductility compared to those fabricated by conventional methods was achieved in the as-built samples. Quantitative analysis revealed that the cellular structures contribute significantly to the enhanced strength through dislocation hardening rather than cellular boundary strengthening. The excellent ductility is correlated with the steady strain hardening controlled by the sophisticated dislocation activities.

Subfields: Aerospace Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/6b2109d1164a9caeedb2051c73c5df2512397b65

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Citations in the corpus

Selective laser melting enabling the hierarchically heterogeneous microstructure and excellent mechanical properties in an interstitial solute strengthened high entropy alloy (2019, background): “It was revealed that the cellular structures can contribute to σ y through the dislocation strengthening [18] based on the expression of σρ = MαGbρ1/2, whereM is the Taylor factor (3.”
Research status of laser additive manufacturing for metal: A review (2021, background): “[204] Zhu ZG, Nguyen QB, Ng FL, An XH, Liao XZ, Liaw PK, et al.”
Knowledge of process-structure-property relationships to engineer better heat treatments for laser powder bed fusion additive manufactured Inconel 718 (2019, background): “Because these cells are orders of magnitude smaller than the grain structure of the alloys, the strength of alloys may be augmented through a microstructure-based size effect and/or dislocation hardening; a modified Hall-Petch relationship with a contribution from dislocation cells has shown to mode”
Superior tensile properties of 1%C-CoCrFeMnNi high-entropy alloy additively manufactured by selective laser melting (2020, methodology): “The heat flux at the (N + 1)th layer was directly transferred through the Nth layer, with the formation of a columnar grain structure, by epitaxial solidification along the side opposite to the building direction [10].”
The origin of high-density dislocations in additively manufactured metals (2020, background): “By a closer examination of the grain structures on the etched surface, we found coarse grains grew epitaxially from theMP boundaries (Figure 1(c)), which phenomenon had been commonly observed and well elucidated in many L-PBF metals [6,7,11].”