scholarly journals Temperature Dependence of Viscosity in Supercooled Liquid of Cu-Zr Bulk Metallic Glass by Molecular Dynamics

2013 ◽  
Vol 62 (3) ◽  
pp. 172-178 ◽  
Author(s):  
Narumasa MIYAZAKI ◽  
Masato WAKEDA ◽  
Shigenobu OGATA
Keyword(s):  
Molecular Dynamics ◽  
Metallic Glass ◽  
Temperature Dependence ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid

Resonant vibration analysis for temperature dependence of elastic properties of bulk metallic glass

2007 ◽  
Vol 22 (2) ◽  
pp. 533-537 ◽  
Author(s):  
Sven Bossuyt ◽  
Sixto Giménez ◽  
Jan Schroers
Keyword(s):  
Metallic Glass ◽  
Temperature Dependence ◽  
Bulk Metallic Glass ◽  
Elastic Constants ◽  
Thermal History ◽  
Vibration Analysis ◽  
Supercooled Liquid ◽  
Resonant Vibration ◽  
Impulse Excitation ◽  
Calorimetry Data

The variation of a Zr57Nb5Cu15Ni13Al10 bulk metallic glass’s elastic constants with temperature and thermal history was investigated, using an impulse excitation technique for resonant vibration analysis. The Young’s modulus at 550 K is 78 GPa with a slope of −17 MPa/K in the glass as-produced and increases to 80 GPa with a slope of −26 MPa/K upon annealing. The modulus of the supercooled liquid at 700 K is 74 GPa with a slope of −90 MPa/K, whereas for the crystallized material E = 100 GPa with a slope of −15 MPa/K. These results are interpreted in terms of the vibrational and configurational contributions to the temperature dependence and compared with calorimetry data.

scholarly journals Effects of Annealing on Enthalpy Recovery and Nanomechanical Behaviors of a La-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Structural Relaxation ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Nanoindentation Measurement

Structural relaxation and nanomechanical behaviors of La65Al14Ni5Co5Cu9.2Ag1.8 bulk metallic glass (BMG) with a low glass transition temperature during annealing have been investigated by calorimetry and nanoindentation measurement. The enthalpy release of this metallic glass is deduced by annealing near glass transition. When annealed below glass transition temperature for 5 min, the recovered enthalpy increases with annealing temperature and reaches the maximum value at 403 K. After annealed in supercooled liquid region, the recovered enthalpy obviously decreases. For a given annealing at 393 K, the relaxation behaviors of La-based BMG can be well described by the Kohlrausch-Williams-Watts (KWW) function. The hardness, Young’s modulus, and serrated flow are sensitive to structural relaxation of this metallic glass, which can be well explained by the theory of solid-like region and liquid-like region. The decrease of ductility and the enhancement of homogeneity can be ascribed to the transformation from liquid-like region into solid-like region and the reduction of the shear transition zone (STZ).

Strong Liquid Behavior of Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Forming Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Ralf Busch ◽  
Andreas Masuhr ◽  
Eric Bakke ◽  
William L. Johnson
Keyword(s):  
Glass Transition ◽  
Melting Point ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Glass Transition Region ◽  
Glass Forming ◽  
Liquid Behavior ◽  
Metallic Liquids ◽  
Microscopic Origin

ABSTRACTThe viscosities of the Zr46.75Ti8.25Cu7.5Ni10Be27.5 and the Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass forming liquids was determined from the melting point down to the glass transition in the entire temperature range of the supercooled liquid. The temperature dependence of the viscosity in the supercooled liquid obeys the Vogel-Fulcher-Tammann (VFT) relation. The fragility index D is about 20 for both alloys and the ratio between glass transition temperature and VFT temperature is found to be 1.5. A comparison with other glass forming systems shows that these bulk metallic glass formers are strong liquids comparable to sodium silicate glass. Furthermore, they are the strongest among metallic glass forming liquids. This behavior is a main contributing factor to the glass forming ability since it implicates a higher viscosity from the melting point down to the glass transition compared to other metallic liquids. Thus, the kinetics in the supercooled liquid is sluggish and yields a low critical cooling rate for glass formation. The relaxation behavior in the glass transition region of the alloys is consistent with their strong glassy nature as reflected by a stretching exponent that is close to 0.8. The microscopic origin of the strong liquid behavior of bulk metallic glass formers is discussed.

The oxidation behavior of a novel Ni-free Zr–Cu-based bulk metallic glass composite in the supercooled liquid and crystallization states

2014 ◽  
Vol 53 ◽  
pp. 34-39 ◽  
Author(s):  
Huei-Sen Wang ◽  
Wei-Hau Li ◽  
Mei-Hui Wu ◽  
Hou-Guang Chen ◽  
Jason Shian-Ching Jang ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Oxidation Behavior ◽  
Supercooled Liquid ◽  
Glass Composite ◽  
Bulk Metallic Glass Composite

Nanoscale Molding of a Zirconium Based Bulk Metallic Glass

2007 ◽  
Author(s):  
Kavic Rason ◽  
Brad Kinsey
Keyword(s):  
Aspect Ratio ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
High Aspect Ratio ◽  
Supercooled Liquid ◽  
Mold Material ◽  
Molding Process ◽  
Silicon Mold ◽  
Interfacial Energies ◽  
A Value

Geometrically complex, high aspect ratio microstructures and limited aspect ratio nanostructures have been successfully fabricated in supercooled Bulk Metallic Glass (BMG) substrates by molding against patterned Silicon and Silicon dioxide substrates. However, demand exists for similar metallic substrates with high aspect ratio, nanoscale features. Van Der Waals based interfacial energies between the supercooled liquid BMG and the Silicon cavity represent a substantial obstacle to the direct scaling of the molding process to the nanoscale. In an effort to investigate these effects, experiments were conducted using molds of various compositions: Silicon, SiO2 and SiO2 coated with Gold. The Gold coating failed to impact molding performance due to the thin layer deposited. However, drastically superior results were obtained by using a Silicon mold because of the variation in interfacial interaction between the BMG and the mold material. In addition, a theoretical model to predict achievable aspect ratio is presented and was found to be in qualitative agreement with experimental results. Finally, a value for the surface tension of Viterloy-1b within it’s supercooled liquid state was deduced from experimental data.

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