Materials World Network: Characterization and Modeling of the Interplay between Grain Boundaries and Heterogeneous Plasticity in Titanium

材料世界网络：钛晶界与异质塑性之间相互作用的表征和建模

• 批准号: 1108211
• 负责人: Thomas Bieler
• 金额: $ 48万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1108211&HistoricalAwards=false
• 关键词: Materials; World; Network; Characterization; Modeling

The strengthening effect of grain boundaries is one of the key components in the development of modern structural materials which is responsible for beneficial effects arising from ultra fine grained and nanostructured materials, and grain boundary engineering. The precise nature of the often beneficial effects of grain boundaries, however, has not been understood to a level which would allow for theory-guided optimization of microstructures and accelerated alloy development. In this research, based on collaboration between Michigan State University (MSU) and the Max Planck Institut für Eisenforschung (MPIE) in Düsseldorf, Germany, the investigators combine, improve, and apply recently developed approaches to examine and quantify the micromechanical behavior of grain boundaries using techniques based upon microscopy and conical indentation tests. Combined use of electron backscattered electron pattern mapping, atomic force microscopy, 3-D x-ray characterization, and focused ion beam/electron imaging methods provide quantified measures of activated slip behavior. These methods are used to assess deformation caused by conical indentation to relate detailed indentation topographies to the plastic anisotropy of single crystals. The methods provide an efficiency advantage over traditional single and bi-crystal experiments. Initially, ?single crystal? characterization will occur using indents in grain interiors, and as modeling fidelity is developed using dislocation density based constitutive models implemented in crystal plasticity finite element analyses, indentations near and on grain boundaries will be used to assess the grain boundary transmissivity of slip and mechanical twinning behavior. From observed transmissivity behavior, models for grain boundary transmissivity will be implemented into the constitutive models.The implemented approach, combined with state of the art characterization and simulation methods, can lead to a quantitative understanding of the interplay between grain boundaries and heterogeneous plasticity in titanium polycrystals. Complementary skills in characterization (MSU) and simulation (MPIE) are available to reach the stated goals. Extensive exchanges between the two laboratories occur principally during summers in order to integrate experimental and analytical outcomes.

晶界的强化效应是现代结构材料发展的关键组成部分之一，其负责超细晶和纳米结构材料以及晶界工程所产生的有益效果。然而，晶界通常有益的效果的确切性质还没有被理解到允许理论指导的微观结构优化和加速合金开发的水平。在这项研究中，密歇根州立大学（MSU）和马克斯普朗克研究所für Eisenforschung（MPIE）在杜塞尔多夫，德国之间的合作的基础上，研究人员结合联合收割机，改进，并应用最近开发的方法来检查和量化的微观力学行为的晶界使用技术的基础上显微镜和锥形压痕测试。结合使用电子背散射电子图案映射，原子力显微镜，3-D X射线表征，和聚焦离子束/电子成像方法提供了量化的措施，激活滑移行为。这些方法用于评估由锥形压痕引起的变形，以将详细的压痕形貌与单晶的塑性各向异性相关联。该方法提供了比传统的单晶和双晶实验的效率优势。最初，？单晶？将使用晶粒内部的凹痕进行表征，并且由于使用晶体塑性有限元分析中实施的基于位错密度的本构模型来开发建模保真度，因此将使用晶界附近和晶界上的凹痕来评估滑移的晶界透射率和机械孪晶行为。从观察到的相变行为，晶界相变模型将被实施到本构模型中。实施的方法，结合最先进的表征和模拟方法，可以导致定量地了解钛多晶体中晶界和非均匀塑性之间的相互作用。在表征（MSU）和模拟（MPIE）的补充技能，可达到既定的目标。两个实验室之间的广泛交流主要发生在夏季，以整合实验和分析结果。