Crystallization of Al<SUB>2</SUB>FeZr<SUB>6</SUB> Amorphous Alloy Prepared by Mechanical Alloying

Abstract

Amorphous Al 2 FeZr 6 alloy was prepared from elemental powders by mechanical alloying. The microstructure evolution was identified by X-ray diffraction. The thermal stability of amorphous Al 2 FeZr 6 was determined by DTA. There are two overlapped exothermic peaks observed in curves of DTA. This indicates that two exothermic reactions in the procedure of crystallization of amorphous Al 2 FeZr 6 alloy. The effective activation energies of crystallization were evaluated using Kissinger's plot. The evaluated values of effective activation energy corresponding to the first and the second exothermic reactions are 266 and 299 kJ/mole respectively. The products of crystallization of amorphous Al 2 FeZr 6 alloy are binary intermetallic compounds AlZr 2 and FeZr 2 instead of intermetallic compounds Al 2 FeZr 6 . It was explained by comparing their relative stabilities based on enthalpies of formation of intermetallic compounds.

The formation and crystallization of amorphous Al65Fe20Zr15

“…There is only one exothermic peak, which represents the crystallization of the amorphous phase, at a temperature range 870-960 K with a peak temperature of 913 K (heating rate 20 K min À1 ). This is different from that of Al 2 FeZr 6 [10], in which there are two overlapped peaks. It also shows that the peak temperatures shift to high temperature as the heating rate increases just as that of Al 2 FeZr 6 .…”

“…The incomplete ordered L1 2 phase was observed by mechanical alloying of Al-25Zr-3Fe and Al-25Zr-8Fe [9]. The crystallization of amorphous Al 2 FeZr 6 indicated that there were no ternary intermetallic compounds formed [10]. Nano-amorphous phases were obtained by mechanical alloying of (AlFe) 1Àx Zr x (x = 20, 33.3) [11].…”

Formation enthalpies of Al–Fe–Zr–Nd system calculated by using geometric and Miedema's models

“…Recently, lots of works have been performed for Al-Fe and Al-Fe-Zr systems [4][5][6][7][8][9][10][11][12][13]. Especially, the FeAl alloys offer a combination of attractive properties such as a high specific strength, good strength at intermediate temperature and an excellent corrosion resistance at elevated temperature under oxidizing, carburizing and sulfidizing atmospheres [12].…”