Rheological behavior of Cu–Zr-based metallic glass in the supercooled liquid region

• The activation volume of Zr46Cu38Ag8Al8 in high-temperature deformation is 284–329 Å3.
• The S parameter of Zr46Cu38Ag8Al8 is 0.2, same with Zr65Al10Ni10Cu15.
• The power dissipation map of Zr46Cu38Ag8Al8 exhibited it has excellent workability.

The high temperature rheological behaviors of Zr46Cu38Ag8Al8 and Cu46Zr45Al7Y2 bulk metallic glasses in supercooled liquid region have been investigated by uniaxial strain rate jump compression tests. The results indicate that the high temperature rheological behaviors are sensitive to strain rate and temperature. The rheological behavior will transform from non-Newtonian flow to Newtonian flow with the decrease of strain rate as well as the increase of temperature, which can be explained in the framework of transition state theory. And the rheological behavior of Zr46Cu38Ag8Al8 bulk metallic glass in high temperature is better than that of Cu46Zr45Al7Y2 bulk metallic glass. In addition, the parameter S of both metallic glasses are in a middle level compared with typical bulk metallic glasses, which shown that the metallic glass has an excellent formability in its supercooled liquid region. The optimum domain for thermal workability of these alloys in supercooled liquid region have been roughly located by the deformation map and the power dissipation map, in which the power dissipation efficiency is larger than 0.8. The larger area of optimum domain in the power dissipation map of Zr46Cu38Ag8Al8 exhibited that this bulk metallic glass presents an excellent workability in its supercooled liquid region, but the workability of Cu46Zr45Al7Y2 is not as good as Zr46Cu38Ag8Al8.