Experimental and Theoretical Study of Ductility in Lamellar Titanium Aluminum

层状钛铝延展性的实验与理论研究

• 批准号: 9626344
• 负责人: Vaclav Vitek
• 金额: --
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-15 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9626344&HistoricalAwards=false
• 关键词: Experimental; Theoretical; Study; Ductility; Lamellar

9626344 Vitek This study is a combined, experimental and theoretical project on mechanisms of plastic deformation in titanium aluminide, TiAl. The experimental portion is used as input for the theoretical portion and vice versa. The objectives of the study are to fully characterize and identify the deformation modes in polysynthetically twinned single crystals and in lamellar polycrystals of TiAl-based alloys, to show how deformation is transmitted across the various types of boundaries (including domain and grain boundaries), and to determine the sources of the dislocations and twins. The experimental techniques to be employed are mechanical tests on single crystals and polycrystals, followed by characterization of the deformation modes using optical, atomic force, and transmission electron microscopy. The theoretical program involves atomistic modeling of dislocation core structures, interfacial reactions, and twinning processes, using a variety of interatomic potentials. The potentials to be used are the embedded atom and/or Finnis-Sinclair type, as well as quantum mechanically- based bond order potentials. The development of new interatomic potentials for use in this non-cubic structure will be an important part of the program, as will the development of new experimental techniques for the determination of deformation modes. %%% The results of the study are expected to be of great utility in understanding how, and under what circumstances, low symmetry materials can be toughened. Furthermore, it could show what techniques might be used to toughen intermetallic compounds. ***

9626344本研究是一项关于钛铝化物TiAl塑性变形机理的实验与理论相结合的研究项目。实验部分用作理论部分的输入，反之亦然。本研究的目的是全面描述和识别TiAl基合金的多晶孪晶和片状多晶中的变形模式，显示变形是如何跨越各种类型的晶界(包括晶界和晶界)的，并确定位错和孪晶的来源。将采用的实验技术是对单晶和多晶进行力学测试，然后使用光学、原子力和透射电子显微镜来表征变形模式。理论程序包括使用各种原子间势对位错核结构、界面反应和孪生过程进行原子模拟。所使用的势是嵌入原子和/或芬尼斯-辛克莱类型的势，以及基于量子力学的键序势。开发用于这种非立方结构的新的原子间相互作用势将是该计划的重要部分，开发用于确定变形模式的新实验技术也将是该计划的重要部分。这项研究的结果有望对理解如何以及在什么情况下增韧低对称性材料有很大的帮助。此外，它还可以显示可以使用哪些技术来增韧金属间化合物。***