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Thermal compression tests of (Zr0.6336Cu0.1452Ni0.1012Al0.12)97.4Er2.6 bulk metallic glass (BMG) were performed at temperature of 410, 420, 430 and 440 °C and strain rates of 5 × 10−4, 10−3, 5 × 10−3 and 10−2 s−1, and a thermal processing map was constructed in the supercooled liquid region. The results indicate that in low strain rate regions (5 × 10−4-10−3 s−1), the processing efficiency range is 70-85% and stress range is 70-120 MPa with temperatures of 410 and 420 °C, and the samples can be thermally processed under relatively small stress and show better fluidity, so temperatures of 410 and 420 °C and the strain rate range of 5 × 10−4-10−3 s−1 are optional thermal processing parameters. When the temperature is 430 °C and the strain rate range is 5 × 10−4-10−2 s−1, the processing efficiency range is 75-85%, and the stress range is 16-106 MPa. The (Zr0.6336Cu0.1452Ni0.1012Al0.12)97.4Er2.6 BMG can be thermoformed under smaller flow stress and shows excellent fluidity; therefore, 430 °C and 5 × 10−4-10−2 s−1 also are optional thermal processing parameters. [ABSTRACT FROM AUTHOR]

In this paper, the rheological behavior and thermoplastic deformation of Zr 61.88 Cu 18 Ni 10.12 Al 10 bulk metallic glasses (BMGs) in the supercooled liquid region (SCLR) were studied by high temperature compression tests and a processing map was constructed. The results indicated that the flow stress of present alloy in the SCLR is very sensitive to temperature and strain-rate. The flow stress decreases with increasing temperature and decreasing strain-rate. The viscosity coefficient of the present alloy ranges from 10 11  Pa.s to 10 9  Pa.s and decreases with increasing temperature and strain-rate. When the strain-rate is greater than 5 × 10 −3  s −1 , the Zr 61.88 Cu 18 Ni 10.12 Al 10 alloy undergoes a transition from Newtonian fluid to non-Newtonian fluid. The surface profile exhibited a similar shape of the letter ‘N' after high temperature compression in the deeply SCLR. The optimum hot processing region of Zr 61.88 Cu 18 Ni 10.12 Al 10 alloy is 688 K–708 K with a low strain-rate and 708 K–723 K with a high strain-rate. [ABSTRACT FROM AUTHOR]

In this study, different peak loads and varying cooling rates on creep behavior of (Zr 0.6336 Cu 0.1425 Ni 0.1012 Al 0.12) 97.4 Er 2.6 bulk metallic glass were studied by nanoindentation tester and atomic force microscopy (AFM). The results show that the change of different load and cooling rate has a great influence on the creep behavior of the alloy. Under high peak load conditions, the increasing of the creep displacement and the stress exponent (n) show strong indentation size effect. The hardness of the specimen without rare earth element is 5 times larger than the specimen with rare earth element. With the increase of the cooling rate, the creep displacement of the specimen is increasing and the time to enter the steady state creep is prolonging. The hardness and elastic modulus of the material are sensitive to the cooling rate relative to the load change. • The hardness of specimen without adding Er is 5 times larger than specimen adding Er. • Creep behavior of materials is more sensitive to changes in cooling rates than loads. • The influence upon the creep behavior becomes slighter with the peak load decreasing. [ABSTRACT FROM AUTHOR]