Deformation Behavior of Metallic-glass Wires and Enhancement

发布时间：2023-02-07 13:25

　　由于金属玻璃丝的几乎无塑性,其通常会发生灾难性的断裂。金属玻璃丝的断裂机制主要受剪切带的萌生和蔓延控制。高脆性金属玻璃丝的灾难性断裂是没有任何预兆的,从而表明金属玻璃丝的使用性能较差。因此,了解金属玻璃丝的变形与剪切带之间的关系对工程应用至关重要。本文研究了室温条件下Cu₅₀Zr₅₀,Ni₅₆Nb₄₄和Pd₄₀Cu₃₀Ni₁₀P₂₀金属玻璃丝表面电沉积Cu,Ni和Cu/Ni双层金属玻璃丝的拉伸变形行为,强度可靠性和增强塑性。通过X射线衍射仪（XRD）和差示扫描量热仪（DSC）测试金属玻璃丝的无定形结构。通过SEM测定断裂表面形形貌。在金属玻璃丝的断裂表面上可以观察到典型的脉状图案和圆形芯。本研究采用的第二种方法是挤出工艺,也称为冷拔,以均化铸态金属玻璃丝的表面质量。第三种方法是将软韧性金属（Cu）和硬金属（Ni）电沉积到金属玻璃丝的表面以增强其可塑性。通过电化学沉积技术将Cu层电沉积在Pd₄₀

【文章页数】：152 页

【学位级别】：博士

【文章目录】：
Dedication
Acknowledgements
Abstract
摘要
Chapter 1 Introduction
    1.1 Metallic glasses
        1.1.1 History and development of metallic glasses
        1.1.2 Mechanical and Microstructure aspect of MG wires
        1.1.3 Application potential of MGs and metallic glass wires
    1.2 Literature Review
        1.2.1 Flow and plastic deformation behavior of metallic glasses
        1.2.2 Yielding criterion for metallic glasses
    1.3 Motivation and objectives
Chapter 2 Mechanical characterization of MG wires
    2.1 Introduction
    2.2 Experimental procedure
    2.3 Results
        2.3.1 Mechanical characterization of metallic glass wires
        2.3.2 Fractographies of metallic glass wires
    2.4 Discussion
        2.4.1 Relationship between diameter vs normal stress of MG wires
        2.4.2 Cohesion strength as a function of the diameter of wires
    2.5 Conclusions
    2.5 结论
Chapter 3 Tensile strength variations and weibull statistics
    3.1 Introduction
        3.1.1 Applications and key issues of CuZr and NiNb wires
        3.1.2 The Weibull modulus and reliability analysis of wires
        3.1.3 Flaw sensitivity or brittleness in metallic glasses
    3.2 Experimental procedure
    3.3 Results
        3.3.1 Mechanical characterization of metallic glass wires
        3.3.2 Statistical analysis of metallic glass wires
    3.4 Conclusions
    3.4 结论
Chapter 4 Electrochemical deposition and plasticity of metallic glass wires
    4.1 Introduction
        4.1.1 Electrochemical deposition and redox reactions
        4.1.2 Metals (Cu & Ni) electrochemical deposition
        4.1.3 Technique used to improve plasticity of metallic glasses
    4.2 Experimental procedure
    4.3 Results
        4.3.1 Mechanical characterization of Cu-coated metallic glass wires
        4.3.2 Fractographies of Cu-coated metallic glass wires
    4.4 Discussion
        4.4.1 Deformation behavior of Cu-coated metallic glass wires
    4.5 Conclusions
    4.5 结论
Chapter 5 Cu/Ni bilayer electrochemical deposition
    5.1 Introduction
        5.1.1 Electrodeposition of Cu/Ni onto the metallic glasses
        5.1.2 Cu/Ni bilayer coating onto Ni56Nb44 MG wires
    5.2 Experimental procedure
    5.3 Results
        5.3.1 Mechanical characterization of Cu/Ni coated metallic glass wires
        5.3.2 Tensile stress-strain curves of coated NiNb MG wires
    5.4 Discussion
        5.4.1 Fractographies of bilayered Cu/Ni-coated MG wires
    5.5 Conclusions
    5.5 结论
Chapter 6 Overall conclusions and expectations
    6.1 Overall conclusions
    6.1 总体结论
    6.2 Expectations
    6.2 期望
    6.3 Concluding Remarks
    6.3 结束语
References
Curriculum Vitae
Publications
Conference Contributions



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