al u2014 fe alloy several solid solid transitions have been included in this diagram in particular a high temperature phase the so called u03b5 phase 301 is present around the composition al 6 fe 4 this phase prevents a deep eutectic to be present at around 60 at in the al u2014 fe phase diagram which would otherwise be expected by extrapolation as indicated by the dotted line in fig3 however since the eutectics of zr 76 fe 24 and zr 72 5 cu 27 5 are already below 1000 u00b0 c it is likely that the high temperature u03b5 phase which spans a temperature range between 1102 and 1232 u00b0 c will not form any more in the quaternary alloy these considerations led to the development of the composition zr 72 5 cu 27 5 80 fe 40 al 60 20 as a starting point for further investigations as detailed below it was found that this alloy even without any further refinement of the composition exhibits excellent glass forming ability in addition the composition of the alloy was varied and it was found that the alloy retained its good glass forming properties in a rather wide range of compositions this shows that the u201c 80 20 concept u201d can be successfully generalized to quaternary alloys the concept is believed to be generally applicable and not to be restricted to the particular zr u2014 cu.