|
The crystallization behaviour of amorphous Fe93-xZr7Bx (x = 3, 6,
12 at.%) alloys and the microstructures of the primary crystallization products have
been studied using a combination of differential scanning calorimetry, differential
thermal analysis, x-ray diffraction and transmission electron microscopy. For x = 3
and 6 at.% the sole product of primary crystallization is the bcc (-Fe phase. The
average grain size of the crystalline phase was 13 nm for the Fe90Zr7B alloy heated
to 875 K at 20 K/min and 12 nm for the Fe87Zr7B6 alloy heated to 893 K at 20 K/min.
However, when x = 12, primary crystallization results in a metastable phase with the
cubic "Fe12Si2ZrB" structure and the α-Fe phase. The average grain size of this
metastable phase was 35 nm for the alloy heated to 883 K at 20 K/min. Transformation
of this metastable phase to predominantly bcc α-Fe can be induced by isothermal heat
treatment at sufficiently high temperatures.
|