Glass formation and phase selection of melt-spun Al-Zn-Ce alloys

摘要

The glass-formation characteristics and phase-selection behavior of Al-Zn-Ce alloys have been studied by X-ray diffraction (XRD) and different scanning calorimetry (DSC). As the concentration of Ce increases, an intermetallic compound Al2Zn2Ce appears, which prevents the occurrence of phase separation, and improves the forming ability of the single amorphous phase. In Al83Zn10Ce7 alloys, the precipitation of fcc-Al was accompanied with the Al2Zn2Ce phase and Al4Ce phase. Moreover, the presence of fcc-Al appears to favor the nucleation and growth of the Al2Zn2Ce and Al4Ce phase. However, it seems that the Al2Zn2Ce and Al4Ce nucleate competitively with the fcc-Al phase and the growth of fcc-Al and Al2Zn2Ce prefers to that of Al4Ce. The competitive nucleation and growth limitation of the various phases are favorable to the formation of Al-Zn-Ce amorphous alloys. For the amorphous Al-Zn-Ce alloys, the glass formation is not controlled by nucleation restrictions but largely by the suppression of growth of nuclei formed during rapid melt quenching.