Stability of amorphous Al90TMxCe10—x（TM=Fe or Ni） alloys

X-ray diffraction(XRD) and differential scanning calorimetry(DSC) were used to investigate the crystallization process of amorphous Al90TMxCe10-x (atom fraction in%;TM=Fe or Ni;x=3,5)alloys,Aging effects were examined by X-ray diffraction,The structure corresponding to the prepeak for the amorphous Al90Fe5Ce5 alloy is more stble than the amorphous matrix,but it is not stable for amorphous Al90Ni5Ce5 alloy during the first crystallization stage and even decomposes at room temperature,Although both Al-Ni and Al-Fe have strong chemical bonding,the cyrstallization onset temperature of amorphous Al-Fe-Ce alloys is much higher than that of amorphous Al-Ni-Ce alloys,which is likely caused by the different stability of the structure corresponding to the prepeak.The crystallization onset temperature increases as Ce/Ni ratio increases in amporphous Al90NixCe10-x alloys,whereas it decreases as Ce/Fe ratio increases in amorphous Al90FexCe10-x alloys.A better atomic packing produces as Ce content increases because of the size mismatch in Al-Ni-Ce systems and as Fe content increases because of the increasing Fe central structural units.

Stability of amorphous Al90TMxCe10-x(TM = Fe or Ni) alloys

X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate the crystallization process of amorphous Al90TM.Ce10-xv (atom fraction in %; TM = Fe or Ni; x = 3, 5) alloys. Aging effects were examined by X-ray diffraction. The structure corresponding to the prepeak for the amorphous Al90Fe5Ce5 alloy is more stable than the amorphous matrix, but it is not stable for amorphous Al90NisCe5 alloy during the first crystallization stage and even decomposes at room temperature. Although both Al-Ni and Al-Fe have strong chemical bonding, the crystallization onset temperature of amorphous AI-Fe-Ce alloys is much higher than that of amorphous Al-Ni-Ce alloys, which is likely caused by the different stability of the structure corresponding to the prepeak. The crystallization onset temperature increases as Ce/Ni ratio increases in amorphous ALNi,Ce10-x , alloys, whereas it decreases as Ce/Fe ratio increases in amorphous AUnFe.Cein , alloys. A better atomic packing produces as Ce content increases because of the size mismatch in Al-Ni-Ce systems and as Fe content increases because of the increasing Fe central structural units.