锆基块体金属玻璃的微米尺度结构不均匀性与宏观力学性能的关联

The aim of the present project is to reveal the characteristics and formation mechanism of micrometer network structures, and to establish the correlation with macro mechanical properties. At first, to characterize the features of micrometer network structures, such as geometrical characteristics, modulus and energy state and so on，and then to figure out the distribution of characteristics parameters of network structures. To analyze the effect of compositions and processes parameters on the network structure statistically and to reveal the formation mechanism of the micrometer network structure. Secondly, to observe the deformation behavior, statistically, to analyze relationship between characters of network structure, such as size and modulus, and macro mechanical properties. And then to analyze relationship between network structure and free volume and shear transformation zone as well as shear band characters. And then to reveal the mechanism of effect of micrometer network structure on deformation behavior, and to propose a mathematical model on relationship between characters of network structure and macro mechanical properties. Thirdly to study the relationship between the network structure and the melt structure evolution, to simulate the effect of the melt structure evolution on micrometer network structure, to reveal the microstructure origination of the reproducibility of the macro mechanical properties, and then to reveal the intrinsic mechanism of the effect of composition and process on the macro mechanical properties and reproducibility. At last, we aim to reveal the correlation and to establish the qualitative/semi-quantitative relationship between macro mechanical properties and micrometer network structure.

本课题旨在探明锆铜镍铝系块体金属玻璃的微米尺度网状结构的本质特征、形成机理及其与宏观力学性能之间的关联。首先，研究微米尺度网状结构的本质特征—几何特征、模量和能量分布等，明确网状结构的特征参数的分布规律，统计分析成分和工艺参数对网状结构特征参数的影响规律，探明网状结构的形成机理。其次，考察网状结构的变形行为，统计分析微米尺度网状结构的特征参数与宏观力学性能之间的对应关系，探明网状结构与自由体积、剪切形变单元和剪切带特征参数之间的联系，揭示微米尺度网状结构对剪切变形行为的影响机理，提出微米尺度网状结构—宏观力学性能关系的数理模型。然后，模拟研究熔体结构的演变和遗传性对网状结构的影响，探明影响宏观力学性能及其再现性的微观结构起源，揭示合金成分和工艺对宏观力学性能及再现性的影响的机理。最后，探明微米尺度网状结构与宏观力学性能的关联规律，建立微米尺度网状结构与宏观力学性能之间的定性/半定量关系。

非晶合金的力学性能与微观结构之间的关系是非晶合金的基本问题之一。研究了Zr-Cu-Ni-Al 系非晶合金的制备工艺及合金成分等对非晶形成能力、结构和性能的影响规律。开发制备出几种具有高强度、大塑性的锆基非晶合金，如Zr63.36Cu14.54Ni10.1Al12非晶合金具有强非晶形成能力和优异的综合力学性能，Zr63.36Cu14.54Ni10.1Al12非晶合金宏观力学性能表现为高强度和大塑性，塑性变形为37.5%，极限强度为2340MPa。研究了Zr-Cu系合金的微观组织与微区力学性能及宏观力学性能关系，初步探明了微观结构不均匀性的形成机理以及对微观和宏观力学性能的影响规律。发现Zr-Cu-Ni-Al系非晶合金的微观和宏观力学性能与微观结构不均匀性有关，尤其是非晶合金的压缩塑性与微观结构不均匀性有很强的关联，表现出显著的尺寸效应。通过研究Zr-Cu-Ni-Al非晶合金过冷液相区的热学性能和力学性能，获得了过冷液相区内热导率、定压比热和热扩散率的数值及随温度的变化规律，探明了温度和应变速率对该成分非晶合金流变行为的影响，确定了热加工工艺范围。研究了合金成分、熔体过热温度和冷却速率对Zr-Cu-Ni-Al非晶合金凝固组织和力学性能的影响，发现合金成分和冷却速率对过冷度、凝固组织和力学性能有明显的影响。探索了稀土元素Y添加对工业原料制备的Zr-Cu-Ni-Al非晶合金的非晶形成能力和力学性能的影响，发现低纯度的海绵锆的加入会明显降低合金的非晶形成能力和力学性能，而添加Y元素能显著提高非晶形成能力和力学性能。由于工业原料大大降低非晶合金的材料成本，研究成果对Zr-Cu-Ni-Al非晶合金的工程应用有重要的意义。