The best glass-forming compositions in Al-Co(or Ni)-Y ternary systems

The present work aims at the investigation of the largest glass-forming abilities in the Al-Co(or Ni)-Y ternary systems. In the reduced isothermal sections of their ternary phase diagrams, the e/a-based composition line passes through three known phases, Al50Co(or Ni)50, Al33Co(or Ni)33Y33 and α-Y. The atomic cluster-based criterion was incarnated into the Co(or Ni)3Y7-Al composition line. The crossing of the two composition lines gives the composition of Al23Co(or Ni)23Y54. The critical diameters for a full glassy state are 4 mm and 3 mm for the Ni-bearing and Co-bearing alloys, respectively. Thermal analysis indicates that the compositions are not eutectic points. The characteristic thermodynamic parameters are Tg = 645 K, Tx = 694 K and Tg/Tm = 0.64 for Al23Ni23Y54 and Tg = 648 K, Tx = 681 K and Tg/Tm = 0.63 for Al23Co23Y54.