Abstract In the present study, we report structural signature and size-dependent mechanical response of frozen-in icosahedral phase (I-phase) embedded in Zr-(Ti, Nb, Al)-(Cu, Ni) bulk metallic glass (BMG)-forming alloys, which exhibit a narrow composition range overlapping between glass and I-phase forming region. Thus, the different sizes of the I-phase from tens of nanoscale precipitates to enhanced icosahedral short-range order in MG matrix can be obtained by controlling cooling history. I-phase particles with tens of nanoscale in BMGs do not contribute to extrinsic ductility due to limited blocking of the propagation of shear band. The shear band passes through the particle, splitting it into two pieces. On the other hand, BMGs with enhanced icosahedral short-range order, which can be evaluated by EXAFS analysis as well as calorimetric signal during isothermal annealing, exhibit enhanced ductility without strength reduction. Indeed, we examine the cut-off size of strain bursts and deformation dynamics of shear-avalanches through the statistical analysis of serration behavior. Icosahedral short-range order (ISRO)-embedded MGs exhibit weakened jammed state of the self-organized deformed zones, which results in the formation of numerous catastrophic deformed zones under relatively chaotic dynamics, and consequently multiple shear bands. These results would help deepen our understanding of the underlying mechanism that determines intrinsic ductility in BMGs via frozen-in ISRO, and ultimately give us a guideline for the design of promising BMGs with improved intrinsic ductility by manipulating local structural instability.

中文翻译：

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块状金属玻璃中冻结二十面体相的结构特征和尺寸相关的机械响应

摘要 在本研究中，我们报告了嵌入 Zr-(Ti, Nb, Al)-(Cu, Ni) 块状金属玻璃 (BMG) 中的冻结二十面体相（I 相）的结构特征和尺寸相关的机械响应形成合金，在玻璃和 I 相形成区域之间显示出狭窄的成分范围重叠。因此，通过控制冷却历史，可以获得不同尺寸的 I 相，从数十个纳米级沉淀物到 MG 基体中增强的二十面体短程有序。由于剪切带的传播受到限制，BMG 中具有数十纳米级的 I 相颗粒对外延性没有贡献。剪切带穿过颗粒，将其分成两部分。另一方面，具有增强的二十面体短程有序的 BMG，可以通过 EXAFS 分析以及等温退火过程中的量热信号进行评估，显示出增强的延展性而不会降低强度。事实上，我们通过锯齿行为的统计分析来检查应变爆发的截止尺寸和剪切雪崩的变形动力学。二十面体短程有序 (ISRO) 嵌入的 MGs 表现出自组织变形区的削弱阻塞状态，这导致在相对混乱的动力学下形成许多灾难性变形区，从而形成多个剪切带。这些结果将有助于加深我们对通过冻结在 ISRO 中决定 BMG 内在延展性的潜在机制的理解，