Study on deformation and fracture behavior of tuicrystals and its application to design of grain boundaries in polycrystals

多晶变形断裂行为研究及其在多晶晶界设计中的应用

基本信息

批准号：
03402045
负责人：
MIURA Sei
金额：
$ 10.56万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

The purpose of this project is to understand the structures of grain boundaries and boundary nodes (triple lines) necessary for strengthening of polycrystals. To achieve the purpose, we have studied roles of a grain boundary and a triple line in deformation and fracture from experiments employing tricrystals. Mains results obtained are summarized as follows.1. We have grown single, bi-and tri-crystals of metals and alloys, and studied deformation and fracture behavior of the crystals by tensile, creep and fatigue tests. Localized deformation and formation and propagation of cracks at and around the grain boundaries and triple lines have been quantitatively and systematically studied including the effects of orientations of the grain boundaries and triple lines. We have revealed contribution of the triple lines to deformation and fracture and its temperature dependence, and presented the structures of grain boundaries and triple lines necessary for the strengthening of materials.2. We have adopted tricrystals consisting of so called special boundaries as main specimens. The same triple lines with the triple lines in the tricrystals have been found in recrystallized copper bicrystals. We have shown the application of the results obtained using the tricrystals to the discussion of mechanical properties of polycrystals.3. Considering the importance of multi-phase materials as practical structural materials, effects of intrphase boundaries on mechanical properties have been studied. We have (gamma/alpha) stainess bicrystals by diffusion bonding and investigated the constraint of grain deformation and the superplastic flow at the interphase boundaries.

该项目的目的是了解强化多晶所需的晶界和边界节点（三重线）的结构。为了实现这一目的，我们通过使用三晶的实验研究了晶界和三重线在变形和断裂中的作用。所得主要结果总结如下： 1．我们生长了金属和合金的单晶、双晶和三晶，并通过拉伸、蠕变和疲劳测试研究了晶体的变形和断裂行为。已经对晶界和三重线及其周围的局部变形以及裂纹的形成和扩展进行了定量和系统的研究，包括晶界和三重线取向的影响。我们揭示了三线对变形和断裂的贡献及其温度依赖性，并提出了材料强化所必需的晶界和三线结构。 2．我们采用了由所谓的特殊边界组成的三晶体作为主要样本。在再结晶的铜双晶中也发现了与三晶中的三重线相同的三重线。我们已经展示了使用三晶获得的结果来讨论多晶的机械性能。 3．考虑到多相材料作为实用结构材料的重要性，研究了相间边界对力学性能的影响。我们通过扩散键合获得了（γ/α）双晶，并研究了晶粒变形的约束和相间边界的超塑性流动。