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

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.