Strong metallic glass: TiZrHfCuNiBe high entropy alloy

The viscosity and fragility of TiZrHfCuNiBe high entropy bulk metallic glass (HE-BMG) in the supercooled liquid region were investigated by the strain-rate jump tests. The Newtonian viscosities of HE-BMG are generally smaller than the conventional MGs due to higher mixing entropy. The fragility parameter was estimated to be 38 and implying that the supercooled liquid of HE-BMG is stronger. The interrelationship between fragility index and glass forming ability is discussed. The defects concentration of HE-BMG is much smaller than the traditional MGs, which enhances the difficulty of atomic rearrangement and further improves the stability of the supercooled liquid.