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Nano-Devitrification and Structural Evolution of Rapidly Solidified Amorphous Al-TM (Cu-Co)-Y (at.%) Alloy
Oral Presentation
Authors
1School of Metallurgy and Materials Engineering, Iran Unversity of Science and Technology (IUST)
2School of Metallurgy and Materials Engineering, Iran University of Science and Technology
Abstract
Primary crystallization of Al86Cu6Co2Y6 (at.%) amorphous alloy in order to determine the values for the activation energy and other kinetic parameters which describe the mechanism of the crystallization by employing non-isothermal models was investigated. Al86Cu6Co2Y6 (at. %) amorphous ribbons were prepared by melt spinning on a chilled copper wheel. The melt spun and subsequently annealed ribbons were investigated through differential scanning calorimetry (DSC), optical microscopy (OM), field emission scanning electron microscopy (FESEM) and X-ray diffraction. The Non-isothermal kinetic parameters of the crystallization process were determined by Kissinger and Moynihan methods. The Johnson–Mehl–Avrami equation was used to interpret the crystallization mechanism. The average amount of Avrami exponent (2.0650.16) concluded that the primary crystallization process occurs through three dimensional diffusion-controlled growth with decreasing rate. The α-Al nanoparticles below 50 nm in size homogeneously embedded in the glassy matrix and intermetallic phases (Al3Y, AlCu3 and Al11Y3) were formed during the first and second stages of crystallization, respectively.
Keywords