项目名称： 纳米金属材料蠕变行为的跨尺度和多尺度效应及主控变形机制的研究

项目编号： No.51471131

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 黄平

作者单位： 西安交通大学

项目金额： 85万元

中文摘要： 本项目拟结合蠕变热激活参量和蠕变力学参量的定量分析研究纳米金属材料的蠕变变形机制。着眼于晶粒大小对应的跨尺度变形机制转变及晶粒尺寸分布对应的多尺度变形机制共存的复杂体系，以面心立方金属为例，探讨微观结构、缺陷尺度与纳米晶蠕变行为的关联性和规律性，特别关注晶界和层错的作用机制，建立以晶粒跨尺度和分布多尺度为主要特征的纳米多晶金属蠕变的材料学及力学模型。采用力-热耦合场下的变温变载蠕变实验，在近室温及低温区间内获取激活能、激活体积、应变率敏感系数等热激活参量及应力指数、蠕变应变率等力学参量，量化分析微观结构特征尺寸对纳米多晶金属蠕变行为的力学响应。揭示蠕变性能与变形机制的纵向跨尺度与横向多尺度效应，尝试澄清纳米尺度晶粒中蠕变在实验表征、理论模型等方面出现的若干矛盾现象，为进一步理解和解释相应的蠕变内在物理机制提供实验和理论支撑。

中文关键词： 纳米晶；表面改性；表面处理；磁控溅射

英文摘要： In present project, we try to investigate the creep deformation mechanism of nanocrystalline metals by quantitatively analyzing both activation parameters and creep related parameters. Focusing on the cross-scale effect corresponding to average grain size and multi-scale effect corresponding to grain size distribution,based on face-centered cubic metal system, investigate the intrinsic connections between microstructure, defect size and creep behavior in nanocrystalline metals, specifically concerning on the mechanism related to grain boundary and staking fault, establishing the material and mechanical models based on the effects of both cross- and multi-scales. By performing creep test at various temperature and mechanical fields, derive activation parameters, i.e., activation energy, activation volume and strain rate sensitivity, and mechanical parameters, i.e., stress exponent, creep rate etc, of creep deformation at near room temperature, quantitatively analysis the mechanical response of the creep behavior from microstructural evolution in nanocrystalline metals. Here we try to indicate the size effect at cross- and multi- scale and related deformation mechanisms, and try to clarify those long-lasting controversial observations in previous studies concerning the creep behavior of nanocrystalline metals. We expect the achievements derived from this project could also be used in corresponding bulk nanocrystalline metals with face-centered cubic lattice structure.

英文关键词： Nanocrystalline;Surface modification;Surface treatment;Sputtering deposition