Monte Carlo Simulation And Experimental Research On Crystallization Behavior Of Zr, Fe Based Amorphous Alloys

The nanocrystallization behaviour of Zr₇₀Cu₂₀Ni₁₀ metallic glass during isothermal annealing is studied by employing a Monte Carlo simulation incorporating with a modified Ising model and a Q-state Potts model. Based on the simulated microstructure and differential scanning calorimetry curves, we find that the low crystal-amorphous interface energy of Ni plays an important role in the nanocrystallization of primary Zr₂Ni. It is found that when TImax (where T_Imax is the temperature with maximum nucleation rate), the increase of temperature results in a larger growth rate and a much finer microstructure for the primary Zr₂Ni, which accords with the microstructure evolution in "flash annealing". Finally, the Zr₂Ni/Zr₂Cu interface energyσ_G contributes to the pinning effect of the primary nanosized Zr₂Ni grains in the later formed normal Zr₂Cu grains.A metallic crystalline/amorphous (c/a) bulk composite was prepared by the slow cooling method after remelting the amorphous Fe₇₈Si₉B₁₃ ribbon. By the X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscope (SEM), the composite consists of the primary dendriteα-Fe (without Si) as well as the amorphous matrix. After annealed at 800K, it is found the uniform spheroid particles formed in the c/a composite after the annealing process, which does not formed in the amorphous ribbon under the various annealing process. Energy dispersive analysis of X-rays (EDAX), SEM and XRD were applied to give more detailed information. The formation and evolution of the particle may stimulate the possible application of the Fe based amorphous alloy in future. Calculated crystalline results and the invariant Q enable us to find that conventional XRD experiments on metals only covered neglectable proportion of In(s) within the entire reciprocal space, then the applicability of Ruland's method on metallic system seems doubtful.