材料科学
合金
高熵合金
热力学
延展性(地球科学)
退火(玻璃)
立方晶系
组态熵
极限抗拉强度
熵(时间箭头)
统计物理学
结晶学
冶金
化学
蠕动
物理
作者
Sriswaroop Dasari,Abhishek Sharma,Chao Jiang,Bharat Gwalani,Wei-Chih Lin,Kai-Chi Lo,Stéphane Gorsse,An‐Chou Yeh,S. Srinivasan,R. Banerjee
标识
DOI:10.1073/pnas.2211787120
摘要
Understanding the local chemical ordering propensity in random solid solutions, and tailoring its strength, can guide the design and discovery of complex, paradigm-shifting multicomponent alloys. First, we present a simple thermodynamic framework, based solely on binary enthalpies of mixing, to select optimal alloying elements to control the nature and extent of chemical ordering in high-entropy alloys (HEAs). Next, we couple high-resolution electron microscopy, atom probe tomography, hybrid Monte-Carlo, special quasirandom structures, and density functional theory calculations to demonstrate how controlled additions of Al and Ti and subsequent annealing drive chemical ordering in nearly random equiatomic face-centered cubic CoFeNi solid solution. We establish that short-range ordered domains, the precursors of long-range ordered precipitates, inform mechanical properties. Specifically, a progressively increasing local order boosts the tensile yield strengths of the parent CoFeNi alloy by a factor of four while also substantially improving ductility, which breaks the so-called strength–ductility paradox. Finally, we validate the generality of our approach by predicting and demonstrating that controlled additions of Al, which has large negative enthalpies of mixing with the constituent elements of another nearly random body-centered cubic refractory NbTaTi HEA, also introduces chemical ordering and enhances mechanical properties.
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