Characterization and modeling of the interplay between grain boundaries and heterogeneous plasticity in titanium

钛晶界与异质塑性之间相互作用的表征和建模

基本信息

批准号：
198771379
负责人：
Professor Dr. Franz Roters, since 5/2015
金额：
--
依托单位：
Max-Planck-Institut für Eisenforschung GmbH (MPIE)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/198771379?language=en
关键词：
Characterization modeling interplay between grain

项目摘要

The strengthening effect of grain boundaries is one of the key components in the development of modern structural materials. This is illustratcd by the intcrisificd research efforts 011 ultra fine grained materials, grain boundary engineering, and nanocrystalline materials over the last decade. The precise nature of the often beneficial effects of grain boundaries, however, have not been understood to a level which would allow for theory guided optimization of microstructures and accelerated alloy development.We propose to combine, improve, and apply recently developed approaches to investigate and quantify the micromechanical behavior of grain boundaries. We will achieve this using a recently developed technique that evaluates indentation topographies to generate a detailed understanding of plastic anisotropy of single crystals. A prominent advantage of the method is its efficiency in generating high quality data that previously could only be generated by careful single and bi-crystal experimentation, which both involve significantly higher amounts of experimental effort. By applying this indentation approach, combined with state of the art characterization and Simulation methods, we will develop a sound understanding of the interplay between grain boundaries and heterogeneous plasticity in titanium polycrystals for the first time.The goals of our research program are: (1) Carry out indentation within the interiors of large grains of a-titanium to effectively collect single crystal data coupled with extensive characterization of the resulting plastic defect fields surrounding the indents. By correlating with models of the indentation, we will arrive at a precise constitutive description of the anisotropic plasticity of single-crystalline titanium. (2) Extend this methodology to indentations close to grain-boundaries, i.e. quasi bi-crystal deformation. (3) Compare the measured characteristics of indentations at grain boundaries to simulated indentations äs predicted by the constitutive model calibrated using the single crystal indentations. This will lead us to qualitative understanding on how different types of grain boundaries modulate the local deformation patterns. (4) Based on this qualitative understanding we will implement a grain boundary transmissivity formulation into our non-local crystal plasticity formulation that fully accounts for all relevant influences from the crystallographic and geometric parameters that describe the boundary and the 3-dimensional relations between deformation Systems on both sides of the interface. (5) This grain boundary aware constitutive model will be validated against the collected indent characteristics. (6) Once the constitutive model has been developed, it will be further validated using data from previously collected high resolution experimental data from a polycrystalline microstructural patch deformed in a bulk specimen.Broad Impact: It is difficult to think of an aspect of material processing that affects society more than being able to reliably predict heterogeneous deformation, which is required before prediction of performance or reliability can be made with physically based confidence. This will be accomplished in a joint research project involving Michigan State University (MSU) and Max-Planck-Institut für Eisenforschung (MPIE) in Düsseldorf, Germany, where mutually useful skills are present which can reach the above goals when integrated into an international cooperative research program. The work will be carried out by 3 Ph.D. students under the guidance of Profs Bieler and Crimp at MSU, and a post-doc and one Ph.D. Student guided by Claudio Zambaldi, Dr. Philip Eisenlohr at MPIE. Extensive exchanges between the two laboratories will occur in order to integrate experimental and analytical methods to reach these goals.

晶界强化效应是现代结构材料发展的关键组成部分之一，这可以从过去十年的超细晶材料、晶界工程和纳米晶材料的深入研究中得到证明。然而，晶界通常有益的影响尚未被理解到能够以理论为指导优化微观结构和加速合金开发的水平。我们建议结合、改进和应用最近开发的方法来研究和开发我们将使用最近开发的技术来量化晶界的微观机械行为，该技术可以评估压痕形貌，以详细了解单晶的塑性各向异性，该方法的一个突出优点是它可以高效地生成以前可以实现的高质量数据。只能通过仔细的单晶和双晶实验来生成，这两者都需要大量的实验工作。通过应用这种压痕方法，结合最先进的表征和模拟方法，我们将对首次研究了钛多晶中晶界与异质塑性之间的相互作用。我们的研究计划的目标是：（1）在大晶粒内部进行压痕，有效收集单晶数据，并广泛表征通过与压痕模型相关联，我们将得到单晶各向异性塑性的精确本构描述。 (2) 将这种方法扩展到接近晶界的压痕，即准双晶变形 (3) 将晶界处压痕的测量特性与使用单晶压痕校准的本构模型预测的模拟压痕进行比较。 (4) 基于这种定性的理解，我们将实施一个grain (5) 该晶界 (6) 一旦开发出本构模型，将使用之前从多晶微结构补片中收集的高分辨率实验数据进一步验证该模型广泛影响：很难想象材料加工的哪个方面比能够可靠地预测异质变形更能影响社会，这是在基于物理的信心预测性能或可靠性之前所必需的。这将通过密歇根州立大学 (MSU) 和位于德国杜塞尔多夫的马克斯普朗克研究所 (MPIE) 的联合研究项目来完成，该项目中存在互用的技能，可以达到当纳入国际合作研究计划时，这项工作将由密歇根州立大学 Bieler 和 Crimp 教授的指导下的 3 名博士生以及 Claudio 指导的一名博士后和一名博士生完成。 Zambaldi 和 MPIE 的 Philip Eisenlohr 博士将在实验和分析方法方面进行广泛交流，以实现这些目标。