Viscous flow in supercooled liquids analyzed in terms of transport theory for random media with energetic disorder

1987 ◽  
Vol 58 (8) ◽  
pp. 767-770 ◽  
Author(s):  
H. Bässler
Keyword(s):  
Viscous Flow ◽  
Random Media ◽  
Transport Theory ◽  
Supercooled Liquids ◽  
Energetic Disorder

scholarly journals Mechanics of Supercooled Liquids

2014 ◽  
Vol 81 (11) ◽  
Author(s):  
Jianguo Li ◽  
Qihan Liu ◽  
Laurence Brassart ◽  
Zhigang Suo
Keyword(s):  
Viscous Flow ◽  
Chemical Potential ◽  
Relative Rate ◽  
Diffusion Flux ◽  
Continuum Theory ◽  
Supercooled Liquid ◽  
Supercooled Liquids ◽  
Thermodynamic Consideration ◽  
Self Diffusion ◽  
Molecular Dimension

Pure substances can often be cooled below their melting points and still remain in the liquid state. For some supercooled liquids, a further cooling slows down viscous flow greatly, but does not slow down self-diffusion as much. We formulate a continuum theory that regards viscous flow and self-diffusion as concurrent, but distinct, processes. We generalize Newton's law of viscosity to relate stress, rate of deformation, and chemical potential. The self-diffusion flux is taken to be proportional to the gradient of chemical potential. The relative rate of viscous flow and self-diffusion defines a length, which, for some supercooled liquids, is much larger than the molecular dimension. A thermodynamic consideration leads to boundary conditions for a surface of liquid under the influence of applied traction and surface energy. We apply the theory to a cavity in a supercooled liquid and identify a transition. A large cavity shrinks by viscous flow, and a small cavity shrinks by self-diffusion.

Viscous Flow Behaviors of Supercooled Liquids of Pre-Annealed Zr55Cu30Al10Ni5 Bulk Metallic Glasses

2007 ◽  
Vol 561-565 ◽  
pp. 1271-1274 ◽  
Author(s):  
Tohru Yamasaki ◽  
S. Maeda ◽  
Takeyuki Kikuchi ◽  
Takeshi Fukami ◽  
Yokoyama Yoshihiko ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Metallic Glasses ◽  
High Speed ◽  
Applied Load ◽  
Flow Behavior ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquids ◽  
Supercooled Liquid Region ◽  
Liquid Region

Viscous flow behavior in supercooled liquid region of as-cast and pre-annealed Zr55Cu30Al10Ni5 bulk metallic glasses has been examined by using a penetration viscometer under high-speed heating rate of 20, 200 and 400 °C/min. Applied load for the cylindrical-shaped penetration indenter with a diameter of 1 mm was varied from 0.049 N to 0.294 N. Viscosity was quite independent of these applied loads. By pre-annealing the bulk metallic glasses at 400 °C, the density of the glasses increased, while the viscosity and the activation energy for viscous flow in their soopercooled liquid decreased with the pre-annealing treatments. Corresponding measurements of the differential thermal calorimetry (DSC) have been also done.

Viscous Flow Behaviour of Supercooled Liquids and Mechanical Properties in Zr-Cu-Ni-Al Bulk Metallic Glasses

2010 ◽  
Vol 654-656 ◽  
pp. 1046-1049 ◽  
Author(s):  
Tohru Yamasaki ◽  
M. Yamada ◽  
T. Mori ◽  
Takeyuki Kikuchi ◽  
Yokoyama Yoshihiko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Viscous Flow ◽  
Heating Rate ◽  
Metallic Glasses ◽  
High Speed ◽  
Bulk Metallic Glasses ◽  
Strong Relationship ◽  
Supercooled Liquids ◽  
Flow Behaviour ◽  
Compression Tests

Viscous flow behaviour of supercooled liquids and mechanical properties in Zr55+XCu30-XNi5Al10 (X=0, 5 and 10 at. %) and Zr65Cu18Ni7Al10 bulk metallic glasses (BMGs) have been examined. Viscosity has been measured by using a penetration viscometer at a high-speed heating rate of 400 K/min. With increasing Zr-content, Tg tended to decrease and Tx tended to increase, resulting Tx (=Tx-Tg) increaseing up to about 170 K under a heating rate of 400 K/min by the DSC analysis. The viscosity lowered about one order of magnitude, e.g., minimum value of the viscosity decreased from 3~4x106 Pa-s for the Zr55Cu30Ni5Al10 and Zr60Cu25Ni5Al10 BMGs down to 5~6x105 Pa-s for the Zr65Cu20Ni5Al10 and Zr65Cu18Ni7Al10 BMGs under the same heating condition. Compression tests were also carried out at a slow strain rate of about 1 x 10-4 s-1 at room temperature. With increasing Zr-content, the apparent yield stress was decreased but the total strain at fracture was increased significantly, suggesting that there is a strong relationship between viscosity and the mechanical properties in these BMGs.

Viscous Flow Behaviors of Supercooled Liquids of Pre-Annealed Zr55Cu30Al10Ni5 Bulk Metallic Glasses

2007 ◽  
pp. 1271-1274
Author(s):  
Tohru Yamasaki ◽  
S. Maeda ◽  
Takeyuki Kikuchi ◽  
Takeshi Fukami ◽  
Yoshihiko Yokoyama ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquids
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