Beryllium as a fast diffuser in bulk metallic glasses

铍作为块状金属玻璃的快速扩散剂

• 批准号: 5258718
• 负责人: Professor Dr. Klaus Rätzke
• 金额: --
• 依托单位: Lehrstuhl für Materialverbunde
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2000
• 资助国家: 德国
• 起止时间: 1999-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5258718?language=en
• 关键词: Beryllium; fast; diffuser; bulk; metallic

Since the discovery of bulk amorphous alloys, which are stable against crystallization in the undercooled liquid state on experimental accessible time scales, it is now possible to verify the various models of the glass transition and the undercooled liquid as well as molecular dynamics simulations in metallic systems. These theories are connected to macroscopic quantities like viscosity and diffusivity and their temperature dependence. Within this project it is intended to investigate the diffusion of 7Be as a small and therefore very fast element in the bulk amorphous alloy Zr46.7Ti8.3Cu7.5Ni10Be27.5 and Pd40Ni10Cu30P20 near the glass transition and in the supercooled state to elucidate the basic diffusion mechanism. For Zr46.7Ti8.3Cu7.5Ni10Be27.5 emphasis will be put on the temperature dependence and comparison with already published data on interdiffusion should allow to study influences of chemistry and the thermodynamic factor. In particular the surprising fact, that in the investigated temperature range the Co diffuses faster than the Be will be investigated thouroghly. Tracer implantation should help to circumvent oxidation problems and allow experiments under various hydrostatic pressures. Different pressure dependencies are indicative of different diffusion mechanisms. For the more stable Pd40Ni10Cu30P20 glass it should be possible to extend the investigations to supercooled liquid to test recent theories about the change of the diffusion mechanism in the temperature interval between the caloric glass transition temperature and the melting temperature.

由于大块非晶合金的发现，这是稳定的结晶在过冷液态实验可访问的时间尺度上，现在可以验证各种模型的玻璃化转变和过冷液体以及分子动力学模拟金属系统。这些理论与宏观量如粘度和扩散率及其温度依赖性有关。在这个项目中，它是一个小的，因此非常快的元素在块体非晶合金Zr46.7Ti8.3Cu7.5Ni10Be27.5和Pd40Ni10Cu30P20的玻璃化转变附近的扩散和在过冷状态，以阐明基本的扩散机制。对于Zr46.7Ti8.3Cu7.5Ni10Be27.5的重点将放在温度的依赖性和比较已经发表的数据相互扩散应允许研究化学和热力学因素的影响。特别是令人惊讶的事实，即在所研究的温度范围内，Co的扩散速度比Be的将被彻底研究。示踪剂的注入应该有助于避免氧化问题，并允许在各种流体静压下进行实验。不同的压力依赖性指示不同的扩散机制。对于更稳定的Pd40Ni10Cu30P20玻璃，应该有可能将研究扩展到过冷液体，以测试最近的理论关于热玻璃化转变温度和熔化温度之间的温度间隔中的扩散机制的变化。