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HEA 2023: Wednesday Plenary
Program Organizers: Andrew Detor, DARPA/DSO; Amy Clarke, Los Alamos National Laboratory

Wednesday 8:00 AM
November 15, 2023
Room: William Penn Ballroom
Location: Omni William Penn

Session Chair: Keith Knipling, Naval Research Laboratory

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8:00 AM Introductory Comments

8:10 AM  Plenary
Designing Chemical Inhomogeneities in Concentrated Complex Alloys to Circumvent The Strength-ductility Trade-off: Evan Ma¹; ¹Xi'an Jiaotong Universty
     In HEAs, the chemical inhomogeneity has two prongs that can be present separately, but sometimes co-exist: i) concentration fluctuation/undulation that can be intentionally enlarged and manipulated [1]); ii) local chemical order [2] that arises from the varying chemical affinity among the constitutent species. Both aspects roughen the atomic and energy landscape, making it easy for the deformation carriers (dislocations and twins) to stall, multiply and accumulate, such that HEAs have an unusal ability to work-harden on the fly with increasing strain. These dynamic effects on defect evolution help delocalize the plastic strain, making it practical to achieve pure-metal-like ductility simultaneously with gigapascal yield strength, including in BCC refractory HEAs [3] that normally suffer from low tensile ductility. [1] H. Li et al., Nature, 604 (2022) 273-279; [2] X. Chen et al., Nature, 592 (2021) 712-716; [3] L. Wang et al., Nature Mater. (2023) April 10.

8:50 AM Break

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