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

Journal Article · Tue Dec 03 00:00:00 EST 2019 · Scripta Materialia

DOI:https://doi.org/10.1016/j.scriptamat.2019.11.053· OSTI ID:1606850

Slone, C. E. ^[1]; LaRosa, C. R. ^[1]; Zenk, C. H. ^[1]; George, Easo P. ^[2]; Ghazisaeidi, M. ^[1]; Mills, Michael J. ^[1]

---

1. The Ohio State Univ., Columbus, OH (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

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. Here, 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.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: National Science Foundation; USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1606850
• Alternate ID(s): OSTI ID: 1797865
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: C Vol. 178; ISSN 1359-6462
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CrCoNi alloy
TWIP steel
deformation twinning
medium- and high-entropy alloys
work-hardening