scholarly journals Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

2011 ◽  
Vol 59 (5) ◽  
pp. 2057-2068 ◽  
Author(s):  
F. Jiang ◽  
M.Q. Jiang ◽  
H.F. Wang ◽  
Y.L. Zhao ◽  
L. He ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Transformation Zone ◽  
Brittle Transition ◽  
Shear Transformation ◽  
Shear Transformation Zone

scholarly journals On Mechanical Properties of Metallic Glass and its Liquid Vitrification Characteristics

2008 ◽  
Vol 41-42 ◽  
pp. 247-252
Author(s):  
Min Qiang Jiang ◽  
L.H. Dai
Keyword(s):  
Elastic Constants ◽  
Metallic Glasses ◽  
Critical Strain ◽  
Molar Mass ◽  
Characteristic Size ◽  
Transformation Zone ◽  
Shear Transformation ◽  
Shear Transformation Zone ◽  
Solid Glass ◽  
Characteristic Volume

A systematic survey of the available data such as elastic constants, density, molar mass, and glass transition temperature of 45 metallic glasses is conducted. It is found that a critical strain controlling the onset of plastic deformation is material-independent. However, the correlation between elastic constants of solid glass and vitrification characteristics of its liquid does not follow a simple linear relation, and a characteristic volume, viz. molar volume, maybe relating to the characteristic size of a shear transformation zone (STZ), should be involved.

Localized heating and fracture criterion for bulk metallic glasses

2006 ◽  
Vol 21 (4) ◽  
pp. 915-922 ◽  
Author(s):  
B. Yang ◽  
C.T. Liu ◽  
T.G. Nieh ◽  
M.L. Morrison ◽  
P.K. Liaw ◽  
...  
Keyword(s):  
Shear Band ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Zone Model ◽  
Transformation Zone ◽  
Localized Heating ◽  
Instantaneous Temperature ◽  
Shear Transformation ◽  
New Criterion

In this study, we demonstrated that the failure of bulk metallic glasses (BMGs) results from a sudden temperature rise within a shear band. Using a shear transformation zone model, we successfully calculated the temperature within a shear band and found it consistent with the observation from an in situ infrared thermographic system. The instantaneous temperature within a shear band at fracture agrees remarkably well with the glass transition temperature (Tg providing a new criterion to determine the strength of BMGs from their Tg. This agreement also discloses the fact that catastrophic failure of BMG is caused by the sudden drop in viscosity inside the shear band when the instantaneous temperature within a shear band approaches Tg.

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