About this Abstract |
Meeting |
2nd World Congress on High Entropy Alloys (HEA 2021)
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Symposium
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2nd World Congress on High Entropy Alloys (HEA 2021)
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Presentation Title |
Solution Thermodynamics Guided Tuning of Local Chemical Ordering in High Entropy Alloys: Implications for Mechanical Properties |
Author(s) |
Sriswaroop Dasari, Abhishek Sharma, Chao Jiang, Bharat Gwalani, Srivilliputhur G Srinivasan, Rajarshi Banerjee |
On-Site Speaker (Planned) |
Rajarshi Banerjee |
Abstract Scope |
Understanding the atomic distributions in random solid solutions and their propensity for local chemical ordering in high entropy alloys (HEAs) has been the subject of intensive recent research. This work presents a simple thermodynamics-based framework, starting from enthalpies of mixing of binary pairs, to guide the design of complex multi-component systems with targeted mechanical properties by controlling the nature and extent of chemical ordering in HEAs. Our framework illustrates how chemical ordering of a nearly random equiatomic CoFeNi solid solution can be tuned by controlled additions of Al and Ti. By coupling high resolution electron microscopy, atom probe tomography, hybrid Monte-Carlo, Special Quasirandom Structures, and density functional theory calculations, we show the presence of short-range ordered domains that are precursors of long-range ordered precipitates and how they inform mechanical properties. We further establish that progressively increasing local order surprisingly boosts the tensile yield strengths of the parent CoFeNi alloy by a factor of four and substantially improves ductility, potentially breaking the so-called strength-ductility tradeoff dilemma in materials. |
Proceedings Inclusion? |
Undecided |