面心立方金属静力韧性的内外尺度效应研究

项目名称： 面心立方金属静力韧性的内外尺度效应研究

项目编号： No.51471128

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： 韩卫忠

作者单位： 西安交通大学

项目金额： 84万元

中文摘要： 晶粒尺寸和样品尺度对金属材料的强度、塑性和韧性有重要影响。本项目拟采用实验和建模相结合的方法，选取各向同性强化的铜和随动强化的铝铜合金，研究其拉伸静力韧性随晶粒尺寸和样品尺度的演化行为。通过研究铜和铝铜合金的静力韧性随晶粒尺寸（100纳米到200微米）的变化，揭示最佳韧性对应的晶粒尺度。通过原位微纳尺度拉伸实验，研究含多个晶界的铜和沉淀强化铝铜合金的静力韧性随样品尺度（100纳米到10微米）的变化，揭示最佳韧性对应的样品尺度。为实现小尺度样品中的位错存储、加工硬化和稳态变形，研究中将引入多个晶界或非剪切沉淀相颗粒。原位研究能揭示位错与晶界或沉淀相的动态交互作用机理，有助于深入理解金属材料的内外尺度效应及其相互关系。基于实验研究，并结合Kock-Mecking等物理模型和进一步理论创新，建立描述典型面心立方金属材料拉伸静力韧性内外尺度效应的新物理模型，为设计高韧性金属结构材料提供指导。

中文关键词： 力学行为；尺寸效应；变形机制；损伤机理；塑性变形

英文摘要： Grain size and sample dimension play a key role in determining the strength, plasticity and toughness of metallic materials. In current project, we intend to reveal the effect of grain size and sample dimension on the toughness of some typical face-centered cubic metallic materials via systematic experimental investigations and physical modeling. Firstly, we will measure the tensile properties of pure Cu and precipitation hardenable Al-4%Cu alloy with different grain size. We try to reveal the effect of grain size on the yielding strength, work hardening, necking behavior, deformation mechanisms and toughness evolution of face-centered cubic metallic materials. Secondly, we will employ in-situ, quantitatively tensile test under TEM to unveil the effect of sample dimension on the yielding strength, work hardening, strain burst, dynamic deformation mechanisms and toughness evolution. In current small volume crystal mechanical tests, we will introduce some grain boundaries with random orientations and unshearable precipitates to prevent commonly observed strain burst and enable dislocation storage thus lead to work hardening and uniform deformation in small volume crystals. The in-situ tensile tests under TEM can reveal the detailed interactions between dislocations and grain boundaries or precipitates, which will assist the understanding of the grain size and sample dimension effect in metals. Lastly, based on the proposed systematic experimental studies and modeling efforts, we will build a new physical model according to Hall-Petch relationship, Kock-Mecking model, Talyor equation and Considère criteria etc to describe the evolution of toughness with grain size and sample dimension in typical face-centered cubic metallic materials. Our systematic experimental studies and the new physical model will guide the quantitatively design and fabrication of high toughness face-centered cubic metallic materials.

英文关键词： Mechanical behavior;Size effect;Deformation mechanism;Damage mechanism;Plastic deformation