Deactivating Deformation Twinning in Medium-Entropy CrCoNi with Small Additions of Aluminum and Titanium
Deactivating Deformation Twinning in Medium-Entropy CrCoNi with Small Additions of Aluminum and Titanium
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DOI：
10.1016/j.scriptamat.2019.11.053
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
C. Slone;C. R. LaRosa;C. Zenk;E. George;M. Ghazisaeidi;M. Mills
中科院分区：
文献类型：
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作者：
C. Slone;C. R. LaRosa;C. Zenk;E. George;M. Ghazisaeidi;M. Mills
等原子CrCoNi和其他多主元素合金的高应变硬化速率归因于变形孪晶。这项工作表明，少量添加Al和Ti到CrCoNi合金中可以抑制变形孪晶，而对均匀伸长率和极限抗拉强度的影响很小。经固溶和淬火后，初始组织中没有富（Al,Ti）的化学有序析出物。报告了合金的拉伸性能，并与等原子CrCoNi进行了比较，并评估了变形后的显微组织。密度泛函理论计算表明，能量上不利的Al-Al键可能通过部分位错阻止剪切，而部分位错是发生孪晶所必需的。
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.