Effect Of High Pressure And Irradiation On Atomic Transportation In Bulk Amorphous Alloys

amorphous alloys under high pressure and proton irradiation have been investigated by secondary ion mass spectroscopy, differential scanning calorimetry and synchrotron radiation x-ray diffraction. Effect of pressure on structural relaxation of Zr₅₇Nb₅Cu_15.4Ni_12.6Al₁₀ bulk amorphous alloy has been studied by in situ high pressure technique. No phase transition was detected from ambient to 32.8 GPa. The equation of state for this alloy can been expressed by the equation as: There is an excess free volume in this bulk amorphous alloy which can be compressed during pressure-induced structure relaxation. It is clearl that compressible volume of the alloy is sensitive to pressure in a lower pressure range. But the compressible volume is smaller when pressure is increased. Self-diffusion of Nb in the bulk amorphous alloy is simulated by diffusion of Mo impurity atoms. The diffusion coefficients increased with temperature from 593 to 673 K, and the activation energy and pre-factor are of 1.95 eV and 1.13×10^-5 m²s^-1, respectively. Effect of pressure on structural relaxation and crystallization kinetics of Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5 bulk amorphous alloy has been studied. The results show that the free volume and enthalpy decrease with increasing pressure. Crystallization activation energy decreases with increasing pressure. Diffusion of Co in Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5 bulk amorphous alloy has been investigated under high pressure at 603 K. The results show that the diffusion coefficient of Co in the bulk amorphous alloy increases with increasing pressure. And the activation volume is obtained to be –1.236Ω which implies that diffusion of Co in this case is in an interstitial-like diffusion mechanism. Viscosity coefficient of the bulk amorphous alloy decreases from 1.79×10¹⁰ Pas at 1 GPa to 1.39×10⁷ Pas at 4 GPa at 603 K. Effect of proton irradiation on structural relaxation and crystallization kinetics of Zr_41.5Ti₁₅Cu_12.6Ni_10.5Be_20.4 bulk amorphous alloy has been investigated. Proton irradiation promotes the atomic movement in this bulk amorphous alloy. And the free volume of the alloy decreases with increasing the dose of the irradiation. The bulk amorphous alloy is more stable after proton irradiated with the dose of 1.1×10¹⁵ and 6.5×10¹⁵ ions/cm², respectively. Crystallization activation energy and electric resistance are decreased when irradiated with the dose of 1.65×10¹⁶ ions/cm², which implies that crystallization are promoted at a higher irradiation dose.