Nanocrystallization kinetics and glass forming ability of the Fe 65 Nb 10 B 25 metallic alloy

摘要: The crystallization kinetics of glassy ${\mathrm{Fe}}_{65}{\mathrm{Nb}}_{10}{\mathrm{B}}_{25}$ melt-spun ribbons is studied by differential scanning calorimetry in the mode continuous heating and isothermal annealing x-ray diffraction transmission electron microscopy. Continuous heat treatments show presence multiple exothermic peaks before melting. low-temperature peak corresponds to precipitation nanoscale ${\mathrm{Fe}}_{23}{\mathrm{B}}_{6}$-type crystalline metastable phase, further leads its transformation into ${\mathrm{Fe}}_{3}\mathrm{B}$ phase subsequent formation $\mathrm{bcc}\text{\ensuremath{-}}\mathrm{Fe}$, ${\mathrm{Fe}}_{2}\mathrm{B}$, FeNbB stable phases. nucleation frequency growth rate are determined at selected temperatures from analysis microstructures that emerge during nanocrystallization. master curve method used obtain apparent activation energy Avrami exponent nanocrystallization onset. explained framework Kolmogorov-Johnson-Mehl-Avrami theory. rejection insoluble alloy atoms primary crystallization, diffusion layers around crystals, decrease caused enrichment residual disordered matrix modeled through a soft impingement factor. Estimated values for interfacial provide satisfactory agreement between experiments modeling derived considering homogeneous interface-controlled grain dominant onset Consequently, time-temperature-transformation diagram also drawn critical cooling estimated this glass forming alloy.