层状TiAl原位透射电镜拉伸揭示界面主导的塑性各向异性  

Revealing interface-assisted plastic anisotropy via in situ transmission electron microscopy tension of lamellar TiAl

作　　者：祁志祥 祝祺 王健 曹月德 陈奉锐 王江伟 陈旸 郑功 陈光 Zhixiang Qi;Qi Zhu;Jian Wang;Yuede Cao;Fengrui Chen;Jiangwei Wang;Yang Chen;Gong Zheng;Guang Chen(State Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology Engineering Research Center of Materials Behavior and Design,Ministry of Education,Nanjing University of Science and Technology,Nanjing 210094,China;Center of Electron Microscopy,State Key Laboratory of Silicon and Advanced Semiconductor Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China;Department of Mechanical&Materials Engineering,University of Nebraska-Lincoln,Lincoln,NE 68583,USA)

机构地区：[1]State Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology Engineering Research Center of Materials Behavior and Design,Ministry of Education,Nanjing University of Science and Technology,Nanjing 210094,China [2]Center of Electron Microscopy,State Key Laboratory of Silicon and Advanced Semiconductor Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China [3]Department of Mechanical&Materials Engineering,University of Nebraska-Lincoln,Lincoln,NE 68583,USA

出　　处：《Science China Materials》2023年第11期4275-4284,共10页中国科学（材料科学（英文版）

基　　金：financially supported by the National Science Foundation of China(52322101,92163215,51731006,51771093,52174364,52101143,52305379);the National Key R&D Program of China(2021YFA1200201);the Fundamental Research Funds for the Central Universities(30922010202)。

摘　　要：基于功能基元和序构范式将功能基元序构成特定取向组织,可以最大限度的利用层状结构材料的力学性能各向异性.然而,其各向异性变形行为的微观起源尚不清楚.本文以全片层的γ-TiAl/α_(2)-Ti_(3)Al双相单晶为模型,通过沿特征取向的原位透射电镜拉伸试验和多尺度结构表征,揭示了界面功能基元主导的塑性各向异性及相应的变形机制.相比于片层内部本征的位错行为,跨γ/α2界面取向序构主导的滑移系连续性和界面强度在塑性各向异性中起决定性作用.因此,当平行或垂直于片层方向拉伸时,层状材料发生穿片层的应力传递或界面分层,进而导致强度和延展性的各向异性.这些机理对理解层状结构材料的塑性各向异性具有普遍意义,有利于高性能合金的结构设计.Assembling functional units into specific or-ientation organizations based on functional unit and organi-zation(FUO)paradigm can maximize utilizing mechanical property anisotropy of lamellar-structured materials.How-ever,the origin of their anisotropic deformation behaviors has not been clearly understood.Taking the fully lamellarγ-TiAl/α2-Ti3Al dual-phase single crystal as an example,we decouple the interface functional units governed anisotropic plastic deformation through in situ transmission electron microscopy tensile testing and multiscale microstructural characteriza-tions.The orientation organization-dependent slip continuity across theγ/α2 interface and interface strength play a de-terminant role in plastic anisotropy beyond intrinsic disloca-tion activities within the lamellae.Consequently,translamellar stress transfer or interface delamination prevails under the tension parallel or perpendicular to the lamella,elaborating the strong anisotropy in strength and ductility.These mechanistic insights hold general implications to un-derstanding the anisotropic plastic deformation of lamellar-structured materials,benefiting the structural design of high-performance alloys.

关 键 词：polysynthetic twinned TiAl anisotropic plastic de-formation slip continuity lamellar-structured materials 

分 类 号：TG146.23[一般工业技术—材料科学与工程]