Publications

Deactivating deformation twinning in medium-entropy CrCoNi with small additions of aluminum and titanium

Slone, C.E. and LaRosa, C.R. and Zenk, C.H. and George, E.P. and Ghazisaeidi, M. and Mills, M.J.

SCRIPTA MATERIALIA
Volume: 178 Pages: 295-300
DOI: 10.1016/j.scriptamat.2019.11.053
Published: 2020

Abstract
High strain-hardening rates in equiatomic CrCoNi and other multi-principal element alloys have been attributed to deformation twinning. This work shows that small additions of Al and Ti to a CrCoNi alloy deactivate deformation twinning with only minor changes to uniform elongation and ultimate tensile strength. The initial microstructure is free of chemically ordered (Al,Ti)-rich precipitates after solutionizing and quenching. Tensile properties for the alloy are reported and compared to equiatomic CrCoNi, and the post-deformation microstructure is assessed. Density functional theory calculations indicate that energetically unfavorable Al-Al bonds may discourage shearing via partial dislocations, which are necessary for twinning to occur. © 2019

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