Microscopic structure and dynamics of bulk metallic glass-forming liquids with minor additions

添加少量添加剂的块体金属玻璃形成液体的微观结构和动力学

• 批准号: 315677471
• 负责人: Professor Dr. Winfried Petry
• 金额: --
• 依托单位: Dipartimento di Fisica
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/315677471?language=en
• 关键词: Microscopic; structure; dynamics; bulk; metallic

Within the current project the microscopic dynamics, viscosity, and the crystallization behavior of the Zr-Cu melts have been studied employing quasielastic neutron scattering, oscillating drop technique, and in-situ synchrotron diffraction, respectively, all combined with the containerless processing technique of electrostatic levitation. We were able to show that alloying a small amount of Al, 4 at %, notably alters the dynamics, as well as the solidification behavior from deeply undercooled melt at Zr50Cu50 liquid. In contrast, the impact of a small Ti addition on the melt dynamics is considerably smaller. First molecular dynamics simulations indicate, that the strong compositional dependence of the melt dynamics upon Al addition may have its origin in the medium range of the liquid. Hence, contributions from chemical short-range order are expected to play an important role in the melt, too. To test this hypothesis i) we intend to alloy a third, non-metallic element like Si (instead of Al) where the impact of the electronic interactions would be even more dominant in metal/non-metal atomic pairs and to apply ii) fluctuation electron microscopy (FEM) to address the important question as to the structural role of the minor addition on glass-forming ability. Together with theory and simulation, this project seeks to better understand the nature of bulk metallic glass formation by identifying the key microscopic role played by the minor addition in enhancing the glass-forming ability of binary alloys. In the framework of the continuation Mr. Szabo will finish his PhD thesis.

在本项目中，分别利用准弹性中子散射、振荡液滴技术和原位同步辐射衍射技术，结合无容器静电悬浮处理技术，研究了锆铜熔体的微观动力学、粘度和结晶行为。我们能够表明，合金化少量的Al，4at%，显著改变了动力学，以及从深过冷的熔体在Zr50Cu50液体的凝固行为。相比之下，添加少量钛对熔体动力学的影响要小得多。首先，分子动力学模拟表明，熔体动力学对Al加入量的强烈成分依赖性可能起源于液体的中等范围。因此，化学短程有序的贡献预计也将在熔化中发挥重要作用。为了验证这一假设，我们打算合金化第三种非金属元素，如Si(而不是Al)，其中电子相互作用的影响在金属/非金属原子对中将更加占主导地位，并应用ii)涨落电子显微镜(FEM)来解决关于少量添加对玻璃形成能力的结构作用这一重要问题。结合理论和模拟，本项目试图通过确定少量添加在提高二元合金非晶形成能力方面所起的关键微观作用来更好地理解块体金属非晶形成的本质。在继续的框架内，萨博先生将完成他的博士论文。