Abstract:Bulk metallic glass (BMG) Cu58Zr20Ti20Mo2 rods with a diameter of 3 mm were prepared by using copper mould suction cast. The structure, thermal stability, compression strength and fracture morphology of this bulk metallic glass were investigated by X-ray diffractometry, differential scanning calorimetry, compression tester and scanning electronic microscopy. The results indicate that a small addition of molybdenum is beneficial for improving glass-forming ability in Cu60Zr20Ti20 system. This amorphous alloy shows a two-stage crystallization, the glass-transition temperature is about 422.6 ℃ and the onset of crystallization temperature is 453.4 ℃. Moreover, this amorphous alloy exhibits a linear relation between the stress and strain and shows a brittle fracture mode. The compression strength is about 1 720 MPa and the elongation about 3.4%. The surface morphology of fracture shows a clear vein pattern. The characteristics of both compression behaviour and fracture of Cu57Zr20Ti20Mo3 alloy with a small amount of amorphous phase are similar to those of the above fully amorphous alloy, but the strength decreases to 1 546 MPa, the elongation is 3.4% and the vein pattern becomes a little disordered and some liquid drops can be observed in the fracture surface.

Key words: CuZrTiMo bulk amorphous alloy; thermal stability; stress—strain curve; fracture morphology