Beryllium as a fast diffuser in bulk metallic glasses

• Applicant: Professor Dr. Klaus Rätzke
• Subject Area: Condensed Matter Physics
• Term: from 2000 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5258718

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.

• DFG Programme: Research Grants
• Participating Person: Professor Dr. Franz Faupel