Effect of Ti addition on supercooled liquid region and glass forming ability of bulk amorphous Zr60Cu20Ni10-xAl10Tix alloys

The effect of partial substitute of Ti for Ni in bulk metallic glass Zr60Cu20Ni10-xAl10 Ti-x (x = 1, 2, 3, 4, 5) is studied. The results show that the width of the supercooled liquid region DeltaT(x) is enlarged when a small amount (1% - 2%) of Ni is replaced by Ti, but minimized when the replacing amount is over 2%, due to the emergence of exothermic peaks at temperature lower than the previous T-x in DSC curves. Meanwhile, the reduced transition temperature T-rg increases with increasing amount of Ti from 1% to 5(%) in the alloys. The relative glass forming ability shown by wedge-shaped samples of different Ti contents reveals the same trend with that of T-rg. Therefore, it is implied from the above results that a large DeltaT(x) (or a high thermal stability of supercooled liquid) is not necessarily connected with a high glass forming ability.