Diffusion in quasicrystal and amorphous alloy with wide supercooled liquid phase

Self-diffusion of Ni-63 in Zr55Al10Ni10Cu25 amorphous alloy with a wide supercooled liquid region has been measured with an ion-beam sputter-sectioning technique in the temperature range from 530 to 720K. The temperature dependence of the diffusivity above and below the glass transition temperature is significantly different: in amorphous phase D-amorph = 6.8x10(-15) exp(-59+/-2 kJmol(-1)/RT) m(2)s(-1) in supercooled liquid phase D-supercool = 4.5x10(9) exp( -363+/-32 kJmol(-1)/RT) m(2)s(-1). The activation energy for diffusion in the supercooled liquid phase is much larger than that in amorphous phase below the glass transition temperature. Diffusion of Mn-54 and Ge-68 in single grain Al70Pd21.5Mn8.5 icosahedral quasicrystal has been investigated by a precision grinding technique over the temperature range from 870 to 1100 K. The temperature dependence of the diffusivities of Mn and Ge in the quasicrystal follows the Arrhenius equation. The temperature dependence of the diffusivities of Mn and Ge is, respectively, expressed as D-Mn = 3.4x10(-4) exp( -181+/-5 kJmol(-1)/RT) m(2)s(-1) D-Ge = 1.4x10(-4) exp( -148+/-7 kJmol(-1)/RT) m(2)s(-1). The diffusivity of Mn in single grain Al70Pd21.5Mn8.5 icosahedral quasicrystal is similar to that of Mn in crystalline Al. The diffusion mechanism in the supercooled liquid phase and the amorphous phase of the Zr55Al10Ni10Cu25 metallic glass and the single grain Al70Pd21.5Mn8.5 icosahedral quasicrystal is discussed.