Crystallization Kinetics of Al-Fe and Al-Fe-Y Amorphous Alloys Produced by Mechanical Milling

الملخص EN

In this work, the effect of a slight change in the composition of the Al-Fe amorphous alloys (from Al84Fe16 to Al82Fe18) and the substitution of Y for Al (2 at.%) on their crystallization kinetics was studied.

According to the X-ray diffraction analysis, powders of the Al84Fe16, Al82Fe18, and Al82Fe16Y2 alloys with a fully amorphous structure were formed after 100 h of mechanical milling of the mixtures of the elemental powders.

The crystallization behavior of the alloys was also studied by transmission electron microscopy.

Upon heating up to a temperature of the first exothermic peak, α-Al crystals precipitated from the amorphous Al84Fe16 matrix.

During crystallization of the Al82Fe18 alloy, crystals of the Al6Fe intermetallic compound formed along with α-Al crystals.

Substitution of Y for 2 at.% of Al in the Al82Fe16Y2 alloy made crystallization of the alloy more complicated: α-Al, Al6Fe, and Fe4Y crystals coexisted with an amorphous phase.

The activation energies corresponding to the first crystallization event of the alloys were calculated using the Kissinger and Ozawa methods.

The values obtained by these two methods were in good agreement with each other and the same trends of changing with the alloy composition were observed.

The Avrami exponent n was determined from the Johnson-Mehl-Avrami equation and showed that crystallization at the first stage is interface-controlled growth for all the three powder alloys studied.