Ni tracer diffusion in the bulk metallic glasses Zr41Ti14Cu12.5Ni10Be22.5 and Zr65Cu17.5Ni10Al7.5

The bulk metallic glasses Zr41Ti14Cu12.5Ni10Be22.5 and Zr65Cu17.5Ni10Al7.5 were produced from the melt which is possible with moderate cooling rates. These materials can be heated about 100 K above their glass transition temperature for rather long times without crystallization. Self-diffusion measurements of Ni-63 in Zr41Ti14Cu12.5Ni10Be22.5 and Zr65Cu17.5Ni10Al7.5 employing the radiotracer method and sputter sectioning are reported. The measurements were performed below and above the glass transition temperature, i.e., in the glassy state and in the supercooled liquid state. The Ni results are compared to diffusion measurements of Be, Co and Al in Zr41Ti14Cu12.5Ni10Be22.5. Effects of structural changes are discussed.