On the nature of heat effects and shear modulus softening in metallic glasses: A generalized approach

2014 ◽  
Vol 115 (3) ◽  
pp. 033513 ◽  
Author(s):  
N. P. Kobelev ◽  
V. A. Khonik ◽  
A. S. Makarov ◽  
G. V. Afonin ◽  
Yu. P. Mitrofanov
Keyword(s):  
Shear Modulus ◽  
Metallic Glasses ◽  
Heat Effects

scholarly journals Metallic Glasses: A New Approach to the Understanding of the Defect Structure and Physical Properties

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 605 ◽  
Author(s):  
Vitaly Khonik ◽  
Nikolai Kobelev
Keyword(s):  
Shear Modulus ◽  
Physical Properties ◽  
Experimental Verification ◽  
Metallic Glasses ◽  
Structural Relaxation ◽  
Defect Structure ◽  
Relaxation Phenomena ◽  
Volume Changes ◽  
New Approach ◽  
Heat Effects

The work is devoted to a brief overview of the Interstitialcy Theory (IT) as applied to different relaxation phenomena occurring in metallic glasses upon structural relaxation and crystallization. The basic hypotheses of the IT and their experimental verification are shortly considered. The main focus is given on the interpretation of recent experiments on the heat effects, volume changes and their link with the shear modulus relaxation. The issues related to the development of the IT and its relationship with other models on defects in metallic glasses are discussed.

Thermodynamic approach for the understanding of the kinetics of heat effects induced by structural relaxation of metallic glasses

2021 ◽  
Author(s):  
Andrey Makarov ◽  
Gennadii V Afonin ◽  
Alexander S Aronin ◽  
Nikolai Kobelev ◽  
Vitaly A Khonik
Keyword(s):  
Shear Modulus ◽  
Metallic Glasses ◽  
Structural Relaxation ◽  
Entropy Change ◽  
Free Energy Barrier ◽  
Novel Approach ◽  
Heat Effects ◽  
Kinetics Of ◽  
Good Agreement ◽  
Non Equilibrium

Abstract We present a novel approach to the understanding of heat effects induced by structural relaxation of metallic glasses. The key idea consists in the application of a general thermodynamic equation for the entropy change due to the evolution of a non-equilibrium part of a complex system. This non-equilibrium part is considered as a defect subsystem of glass and its evolution is governed by local thermoactivated rearrangements with a Gibbs free energy barrier proportional to the high-frequency shear modulus. The only assumption on the nature of the defects is that they should provide a reduction of the shear modulus – a diaelastic effect. This approach allows to determine glass entropy change upon relaxation. On this basis, the kinetics of the heat effects controlled by defect-induced structural relaxation is calculated. A very good agreement between the calculation and specially performed calorimetric and shear modulus measurements on three metallic glasses is found.

On the origin of heat effects and shear modulus changes upon structural relaxation and crystallization of metallic glasses

2017 ◽  
Vol 475 ◽  
pp. 48-52 ◽  
Author(s):  
G.V. Afonin ◽  
Yu.P. Mitrofanov ◽  
A.S. Makarov ◽  
N.P. Kobelev ◽  
V.A. Khonik
Keyword(s):  
Shear Modulus ◽  
Metallic Glasses ◽  
Structural Relaxation ◽  
Heat Effects

scholarly journals Heat Effects Occurring in the Supercooled Liquid State and Upon Crystallization of Metallic Glasses as a Result of Thermally Activated Evolution of Their Defect Systems

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 417 ◽  
Author(s):  
Andrei Makarov ◽  
Gennadii Afonin ◽  
Yurii Mitrofanov ◽  
Nikolai Kobelev ◽  
Vitaly Khonik
Keyword(s):  
Metallic Glasses ◽  
Liquid State ◽  
Supercooled Liquid ◽  
Shear Moduli ◽  
Thermally Activated ◽  
Supercooled Liquid State ◽  
Heat Effects ◽  
Temperature Dependences ◽  
Defect System ◽  
Kinetics Of

We show that the kinetics of endothermal and exothermal effects occurring in the supercooled liquid state and upon crystallization of metallic glasses can be well reproduced using temperature dependences of their shear moduli. It is argued that the interrelation between the heat effects and shear modulus relaxation reflects thermally activated evolution of interstitial-type defect system inherited from the maternal melt.

Predicting temperature dependence of the shear modulus of metallic glasses using calorimetric data

2019 ◽  
Vol 168 ◽  
pp. 10-13 ◽  
Author(s):  
A.S. Makarov ◽  
Yu.P. Mitrofanov ◽  
G.V. Afonin ◽  
N.P. Kobelev ◽  
V.A. Khonik
Keyword(s):  
Shear Modulus ◽  
Temperature Dependence ◽  
Metallic Glasses ◽  
Calorimetric Data

On the origin of the shear modulus change and heat release upon crystallization of metallic glasses

2015 ◽  
Vol 411 ◽  
pp. 1-4 ◽  
Author(s):  
N.P. Kobelev ◽  
V.A. Khonik ◽  
G.V. Afonin ◽  
E.L. Kolyvanov
Keyword(s):  
Shear Modulus ◽  
Heat Release ◽  
Metallic Glasses

Shear modulus and compliance in the range of the dynamic glass transition for metallic glasses

1998 ◽  
Vol 5 (1) ◽  
pp. 1-5 ◽  
Author(s):  
K. Schröter ◽  
G. Wilde ◽  
R. Willnecker ◽  
M. Weiss ◽  
K. Samwer ◽  
...  
Keyword(s):  
Glass Transition ◽  
Shear Modulus ◽  
Metallic Glasses

scholarly journals Elastic Properties and Glass Forming Ability of the Zr50Cu40Ag10 Metallic Alloy

2020 ◽  
Vol 310 ◽  
pp. 145-149 ◽  
Author(s):  
Ramil M. Khusnutdinoff ◽  
Anatolii V. Mokshin
Keyword(s):  
Glass Transition ◽  
Shear Modulus ◽  
Temperature Dependence ◽  
Elastic Properties ◽  
Metallic Glasses ◽  
Liquid Glass ◽  
Glass Forming Ability ◽  
Metallic Alloy ◽  
Poisson's Ratio ◽  
Glass Forming

The elastic properties of the Zr50Cu40Ag10 metallic alloy, such as the bulk modulus B, the shear modulus G, the Young’s modulus E and the Poisson’s ratio σ, are investigated by molecular dynamics simulation in the temperature range T=250–2000 K and at an external pressure of p=1.0 bar. It is shown that the liquid–glass transition is accompanied by a considerable increase in the shear modulus G and the Young’s modulus E (by more than 50%). The temperature dependence of the Poisson’s ratio exhibits a sharp fall from typical values for metals of approximately 0.32–0.33 to low values (close to zero), which are characteristic for brittle bulk metallic glasses. Non-monotonic temperature dependence of the longitudinal and transverse sound velocity near the liquid-glass transition is also observed. The glass forming ability of the alloy is evaluated in terms of the fragility index m. Its value is m≈64 for the Zr50Cu40Ag10 metallic glass, which is in a good agreement with the experimental data for the Zr-based metallic glasses.

Sign in / Sign up

Export Citation Format

Share Document