Thermophysical and mechanical properties of multicomponent Zr37Hf16Ni12.5Cu12.5Al11Co6Nb5 bulk glass-forming alloy.

The Zr37Hf16Ni12.5Cu12.5Al11Co6Nb5 bulk metallic glass (BMG) with strong glass-forming ability (GFA) and remarkable mechanical properties was designed, and its thermophysical properties were characterized simultaneously. The glass transition temperature reached up to 726 K, while the fragility index of 43 was derived by measuring alloy viscosity. The undercooled liquid of this BMG with such a low fragility index displayed a strong liquid behavior, corresponding to its small crystallization driving force and high GFA. The thermal expansion coefficient increased from 9.76 × 10−6 K−1 of glassy state to 2.71 × 10−5 K−1 of undercooled liquid, and the close-packed structure was evidenced by the low specific energy for free volume formation of 239.4 kJ/mol. Owing to its low free volume and high glass transition temperature, this BMG exhibited remarkable tensile and compressive yield strengths up to 1660.3 and 2042.3 MPa, respectively. [ABSTRACT FROM AUTHOR]