Bulk metallic glass formation in Cu-Zr-Ti ternary system

The formation of bulk metallic glasses (BMG) in the Cu-rich Cu-Zr-Ti ternary system is studied by using the 'e/a-variant line criterion'. Three such lines, (Cu9Zr4)(1-x)Ti-x, (Cu61.8Zr38.2)(1-x)Ti-x, and (Cu56Zr44)(1-x)Ti-x, are defined in the Cu-Zr-Ti system by linking three binary compositions Cu9Zr4, Cu61.8Zr38.2 and Cu56Zr44 to the third element Ti. The binary compositions Cu9Zr4, Cu61.8Zr38.2 and Cu56Zr44 correspond to specific Cu-Zr binary clusters. BMGs are obtained by copper mould suction casting method with Ti contents of 7.5-15 at.%, 7.5-12.5 at.% and 5-12 at.%, respectively along the (CugZr4)(1-x)Ti-x, (Cu61.8Zr38.2)(1-x)Ti-x, and (Cu56Zr44)(1-x)Ti-x, lines. The BMGs on each composition line manifest decreased thermal stabilities and glass forming abilities (GFAs) with increasing Ti contents. The maximum GFA appears at Cu64Zr28.5Ti7.5, with characteristic thermal parameters of T-g = 736 K, T, = 769 K, T-g/T-1 = 0.627 and gamma = 0.403, which are all superior to those reported for the known CU60Zr30Ti10 BMG. (c) 2007 Elsevier B.V. All rights reserved.