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Liquid–liquid transition in a strong bulk metallic glass-forming liquid

2013; Nature Portfolio; Volume: 4; Issue: 1 Linguagem: Inglês

10.1038/ncomms3083

2041-1723

Shuai Wei, Fan Yang, Jozef Bednarčík, I. Kaban, O. Shuleshova, Andreas Meyer, Ralf Busch,

Glass properties and applications

Polymorphic phase transitions are common in crystalline solids. Recent studies suggest that phase transitions may also exist between two liquid forms with different entropy and structure. Such a liquid–liquid transition has been investigated in various substances including water, Al2O3-Y2O3 and network glass formers. However, the nature of liquid–liquid transition is debated due to experimental difficulties in avoiding crystallization and/or measuring at high temperatures/pressures. Here we report the thermodynamic and structural evidence of a temperature-induced weak first-order liquid–liquid transition in a bulk metallic glass-forming system Zr41.2Ti13.8Cu12.5Ni10Be22.5 characterized by non- (or weak) directional bonds. Our experimental results suggest that the local structural changes during the transition induce the drastic viscosity changes without a detectable density anomaly. These changes are correlated with a heat capacity maximum in the liquid. Our findings support the hypothesis that the ‘strong’ kinetics (low fragility) of a liquid may arise from an underlying lambda transition above its glass transition. The nature of liquid–liquid phase transitions remains inconclusive, because direct experimental evidence is limited by crystallization. Wei et al.observe it in a bulk metallic glass former, which is characterized by heat capacity maxima and sudden changes in both viscosity and local structures.