由于缺乏位错、晶界等典型的晶格缺陷,金属玻璃体系中承载力的形变单元为短程序或中程序原子团簇,键的强度及成键方向是影响原子间协调变形能力主要因素.本文通过与晶态合金对比,指出金属玻璃中原子键合方式与宏观力学性能的潜在关系,综述了金属材料电子结构与力学性能内在关系的最新研究进展,并系统介绍了金属玻璃电子结构特征、表征参量和主要测试手段,使读者对金属玻璃体系中原子间的键态特征有较清晰的认识,对进一步探索本征塑性较好的金属玻璃体系具有一定指导意义.%Understanding the structure-property relationship of metallic glasses (MGs) at an atomic- or electronic level is a challenging topic in condensed matter physics. MGs usually exhibit low macroscopic plasticity, owing to the localized plastic flow in nano- and micro-meter scale shear bands upon deformation, which impedes their wide application as new structural materials. Thus, a detailed description of internal structure and establishing the structure-property relationship would underpin our knowledge of the mechanisms for the ductility/brittleness of MGs and further improve their plasticity. Due to the lack of structural defects such as dislocations and grain boundaries, the short-or middle-ranged ordered clusters are the typical deformation units in MGs, where the bonding strength and direction between atoms are the key factors that affect the cooperative displacements inside deformation unit. However, the bonding nature of MGs and their structure-property relationship are little studied systematically, which hinders our comprehensive understanding the basic problems about mechanical behaviors of MGs, such as fracture and plasticity deformation mechanism. In this paper, the potential correlation between the flexibility of bonding and ductility of MGs is discussed in detail. The first section gives a simple introduction of this topic. In the second section, the latest research progress of the electronic structural study of MGs is presented. Here, the corresponding studies of electronic structures of crystal alloys and their relationship with the mechanical properties are also presented for comparison. In the third section, the traditional and new experimental techniques employed for electronic structure measurements are presented, such as X-ray photoelectron spectroscopy, ultraviolet photoemission spectroscopy and auger electron spectroscopy and the parameters such as nuclear magnetic resonance knight shift, susceptibility (χ) and specific heat (C) are also given in order to introduce electronic structure analysis methods of MGs and further reveal the bonding character of MGs and recent experimental findings of the relationship between the electronic structure and the mechanical properties of MGs. Numerous studies show that in the typical transition metal (TM)—metalloid metallic glass systems, the bond flexibility or mobility of atoms at the tip of crack that depends on the degree of bonding hybridization, determines the intrinsic plasticity versus brittleness. For instance, in these transition metal (TM)-based MGs, when metalloid element M with sp-element shells is alloyed in the TM matrix, the s-density of states (DOS) at M sites is scattered far below the Fermi level due to the pd hybridization between the p orbitals of M element and the d orbitals of TM. This causes the reduction of s-DOS at the Fermi energy (gs(EF)) at the solute M sites and exhibits a strong directional boning character. Thus, it is proposed that the gs(EF) can be employed as an effective order parameter to characterize the nature of bonding, especially in the aspect of evaluating bond flexibilities in amorphous alloys. This shows that the plastic flow and fracture process of MGs on an atomic scale can be well described using a simple bonding model where the deformation process is accompanied with the broken-down and reforming of atomic bonding inside short-or middle-ranged ordered clusters, since the defects are absent in MGs. We hope that this introduction can provide a much clearer picture of the bonding character of MGs, and further guide us in understanding the mechanism for ductile-to-brittle transition in MGs and exploring the novel MGs with intrinsic plasticity.
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