| Dynamically reinforced heterogeneous grain structure prolongs ductility in a medium-entropy alloy with gigapascal yield strength | |
Yang MX(杨沐鑫) ; Yan DS(严定舜); Yuan FP(袁福平); Jiang P(姜萍); Ma E; Wu XL(武晓雷)
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| Source Publication | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
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| 2018-07-10 | |
| Volume | 115Issue:28Pages:7224-7229 |
| ISSN | 0027-8424 |
| Abstract | Ductility, i. e., uniform strain achievable in uniaxial tension, diminishes for materials with very high yield strength. Even for the CrCoNi medium-entropy alloy (MEA), which has a simple facecentered cubic (FCC) structure that would bode well for high ductility, the fine grains processed to achieve gigapascal strength exhaust the strain hardening ability such that, after yielding, the uniform tensile strain is as low as similar to 2%. Here we purposely deploy, in this MEA, a three-level heterogeneous grain structure (HGS) with grain sizes spanning the nanometer to micrometer range, imparting a high yield strength well in excess of 1 GPa. This heterogeneity results from this alloy's low stacking fault energy, which facilitates corner twins in recrystallization and stores deformation twins and stacking faults during tensile straining. After yielding, the elastoplastic transition through load transfer and strain partitioning among grains of different sizes leads to an upturn of the strain hardening rate, and, upon further tensile straining at room temperature, corner twins evolve into nanograins. This dynamically reinforced HGS leads to a sustainable strain hardening rate, a record-wide hysteresis loop in load-unload-reload stress-strain curve and hence high back stresses, and, consequently, a uniform tensile strain of 22%. As such, this HGS achieves, in a singlephase FCC alloy, a strength-ductility combination that would normally require heterogeneous microstructures such as in dual-phase steels. |
| Keyword | heterogeneous grain structure ductility medium-entropy alloy back stress hardening |
| DOI | 10.1073/pnas.1807817115 |
| URL | 查看原文 |
| Indexed By | SCI |
| Language | 英语 |
| WOS ID | WOS:000438050900050 |
| WOS Keyword | TRANSFORMATION-INDUCED PLASTICITY ; SOLID-SOLUTION ALLOYS ; MECHANICAL-PROPERTIES ; GRADIENT STRUCTURE ; TENSILE PROPERTIES ; STAINLESS-STEEL ; DEFORMATION-BEHAVIOR ; NANOSTRUCTURED METAL ; TWIP STEEL ; EVOLUTION |
| WOS Research Area | Multidisciplinary Sciences |
| WOS Subject | Science & Technology - Other Topics |
| Funding Organization | National Key R&D Program of China [2017YFA0204402] ; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB22040503] ; Natural Science Foundation of China [11572328, 11790293, 11472286] ; US Department of Energy, Division of Materials Sciences and Engineering [DE-FG02-16ER46056] |
| Classification | 一类 |
| Ranking | 1 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://dspace.imech.ac.cn/handle/311007/77831 |
| Collection | 非线性力学国家重点实验室 |
| Affiliation | 1.Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China 2.Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China 3.Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA |
| Recommended Citation GB/T 7714 | Yang MX,Yan DS,Yuan FP,et al. Dynamically reinforced heterogeneous grain structure prolongs ductility in a medium-entropy alloy with gigapascal yield strength[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2018,115,28,:7224-7229. |
| APA | 杨沐鑫,严定舜,袁福平,姜萍,Ma E,&武晓雷.(2018).Dynamically reinforced heterogeneous grain structure prolongs ductility in a medium-entropy alloy with gigapascal yield strength.PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,115(28),7224-7229. |
| MLA | 杨沐鑫,et al."Dynamically reinforced heterogeneous grain structure prolongs ductility in a medium-entropy alloy with gigapascal yield strength".PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 115.28(2018):7224-7229. |
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| IrJ2018216.pdf（1429KB） | 期刊论文 | 出版稿 | 开放获取 | CC BY-NC-SA | View Download | |
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