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Full-Text Articles in Engineering
The Effect Of Thermal History On The Atomic Structure Andmechanical Properties Of Amorphous Alloys, Nikolai V. Priezjev
The Effect Of Thermal History On The Atomic Structure Andmechanical Properties Of Amorphous Alloys, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
The influence of thermal processing on the potential energy, atomic structure, and mechanical properties of metallic glasses is examined using molecular dynamics simulations. We study the three-dimensional binary mixture, which was first relaxed near the glass transition temperature and zero pressure, and then rapidly cooled deep into the glass phase. It was found that glasses annealed at higher temperatures are relocated to higher energy states and their average glass structure remains more disordered, as reflected in the height of the first two peaks in the pair distribution function. The results of mechanical testing demonstrate that both the shear modulus and …
Aging And Rejuvenation During Elastostatic Loading Of Amorphous Alloys, Nikolai V. Priezjev
Aging And Rejuvenation During Elastostatic Loading Of Amorphous Alloys, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
Using molecular dynamics simulations, we investigate the effect of uniaxial elastostatic compression on the potential energy, structural relaxation, and mechanical properties of binary glasses. We consider the three-dimensional Kob-Andersen binary mixture, which was initially cooled from the liquid state to the glass phase with a slow rate at zero pressure. The glass was then loaded with a static stress at the annealing temperature during extended time intervals. It is found that the static stress below the yielding point induces large-scale plastic deformation and significant rejuvenation when the annealing temperature is smaller than a fraction of the glass transition temperature. By …
Atomistic Modeling Of Heat Treatment Processes For Tuning The Mechanical Properties Of Disordered Solids, Nikolai V. Priezjev
Atomistic Modeling Of Heat Treatment Processes For Tuning The Mechanical Properties Of Disordered Solids, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
We investigate the effect of a single heat treatment cycle on the potential energy states and mechanical properties of metallic glasses using molecular dynamics simulations. We consider the three-dimensional binary mixture, which was initially cooled with a computationally slow rate from the liquid state to the solid phase at a temperature well below the glass transition. It was found that a cycle of heating and cooling can relocate the glass to either rejuvenated or relaxed states, depending on the maximum temperature and the loading period. Thus, the lowest potential energy is attained after a cycle with the maximum temperature slightly …
The Influence Of Complex Thermal Treatment On Mechanical Properties Of Amorphous Materials, Nikolai V. Priezjev, Qing-Long Liu
The Influence Of Complex Thermal Treatment On Mechanical Properties Of Amorphous Materials, Nikolai V. Priezjev, Qing-Long Liu
Mechanical and Materials Engineering Faculty Publications
We study the effect of periodic, spatially uniform temperature variation on mechanical properties and structural relaxation of amorphous alloys using molecular dynamics simulations. The disordered material is modeled via a non-additive binary mixture, which is annealed from the liquid to the glassy state with various cooling rates and then either aged at constant temperature or subjected to thermal treatment. We found that in comparison to aged samples, thermal cycling with respect to a reference temperature of approximately half the glass transition temperature leads to more relaxed states with lower levels of potential energy. The largest energy decrease was observed for …
The Effect Of Cryogenic Thermal Cycling On Aging, Rejuvenation, And Mechanical Properties Of Metallic Glasses, Nikolai V. Priezjev
The Effect Of Cryogenic Thermal Cycling On Aging, Rejuvenation, And Mechanical Properties Of Metallic Glasses, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
The structural relaxation, potential energy states, and mechanical properties of a model glass subjected to thermal cycling are investigated using molecular dynamics simulations. We study a non-additive binary mixture which is annealed with different cooling rates from the liquid phase to a low temperature well below the glass transition. The thermal treatment is applied by repeatedly heating and cooling the system at constant pressure, thus temporarily inducing internal stresses upon thermal expansion. We find that poorly annealed glasses are relocated to progressively lower levels of potential energy over consecutive cycles, whereas well annealed glasses can be rejuvenated at sufficiently large …
Slow Relaxation Dynamics In Binary Glasses During Stress-Controlled, Tension-Compression Cyclic Loading, Nikolai V. Priezjev
Slow Relaxation Dynamics In Binary Glasses During Stress-Controlled, Tension-Compression Cyclic Loading, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
The effect of cyclic loading on relaxation dynamics and mechanical properties of metallic glasses is studied using molecular dynamics simulations. We consider the Kob-Andersen three-dimensional binary mixture rapidly cooled across the glass transition and subjected to thousands of tension-compression cycles in the elastic range. It was found that during cyclic loading at constant pressure, the system is relocated to progressively lower levels of the potential energy, thus promoting greater densification and higher strength. Furthermore, with increasing stress amplitude, the average glass density increases and the minimum of the potential energy becomes deeper, while the elastic modulus is reduced. The typical …
The Yielding Transition In Periodically Sheared Binary Glasses At Finite Temperature, Nikolai V. Priezjev
The Yielding Transition In Periodically Sheared Binary Glasses At Finite Temperature, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
Non-equilibrium molecular dynamics simulations are performed to investigate the dynamic behavior of three-dimensional binary glasses prepared via an instantaneous quench across the glass transition. We found that with increasing strain amplitude up to a critical value, the potential energy approaches lower minima in steady state, whereas the amplitude of shear stress oscillations becomes larger. Below the yielding transition, the storage modulus dominates the mechanical response, and the gradual decay of the potential energy over consecutive cycles is accompanied by reduction in size of transient clusters of atoms with large nonaffine displacements. In contrast, above the yield strain, the loss modulus …