Formation of the icosahedral quasicrystalline phase in a rapidly solidified Al52Cu25.5Fe12.5Si10 alloy

In the present work, the effect of wheel speed (quenching rate) on the formation of the quasicrystalline phase in a rapidly solidified Al52Cu25.5Fe12.5Si10 alloy has been investigated using X-ray diffraction (XRD), differential thermal analysis (DTA), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that rapid solidification has no effect on the phase constitution of the Al52Cu25.5Fe12.5Si10 alloy. The addition of Si decreases the stability of the quasicrystalline phase in the conventionally cast Al52Cu25.5Fe12.5Si10 alloy. The thermal stability of the quasicrystalline phase in the melt-spun alloy depends upon the quenching rate. Moderate-rate rapid solidification can improve the thermal stability of the quasicrystalline phase in the melt-spun alloy. Higher quenching rate instigates the transformation of the quasicrystalline phase into the cubic approximant phase and decreases the stability of the quasicrystalline phase. Furthermore, the transformation temperature decreases with increasing Si addition into the Al(62−x)Cu25.5Fe12.5Six.