Dislocation Dynamics and Dynamic Yielding

1965 ◽  
Vol 36 (10) ◽  
pp. 3146-3150 ◽  
Author(s):  
John W. Taylor
Keyword(s):  
Dislocation Dynamics

scholarly journals Theory of the deformation of aligned polyethylene

2015 ◽  
Vol 471 (2180) ◽  
pp. 20150171 ◽  
Author(s):  
A. Hammad ◽  
T. D. Swinburne ◽  
H. Hasan ◽  
S. Del Rosso ◽  
L. Iannucci ◽  
...  
Keyword(s):  
Load Transfer ◽  
Tensile Load ◽  
Equation Of Motion ◽  
Dislocation Dynamics ◽  
Viscoelastic Deformation ◽  
Transfer Length ◽  
Soliton Dynamics ◽  
Fluctuation Dissipation ◽  
Pull Out ◽  
Definition Of

Solitons are proposed as the agents of plastic and viscoelastic deformation in aligned polyethylene. Interactions between straight, parallel molecules are mapped rigorously onto the Frenkel–Kontorova model. It is shown that these molecular interactions distribute an applied load between molecules, with a characteristic transfer length equal to the soliton width. Load transfer leads to the introduction of tensile and compressive solitons at the chain ends to mark the onset of plasticity at a well-defined yield stress, which is much less than the theoretical pull-out stress. Interaction energies between solitons and an equation of motion for solitons are derived. The equation of motion is based on Langevin dynamics and the fluctuation–dissipation theorem and it leads to the rigorous definition of an effective mass for solitons. It forms the basis of a soliton dynamics in direct analogy to dislocation dynamics. Close parallels are drawn between solitons in aligned polymers and dislocations in crystals, including the configurational force on a soliton. The origins of the strain rate and temperature dependencies of the viscoelastic behaviour are discussed in terms of the formation energy of solitons. A failure mechanism is proposed involving soliton condensation under a tensile load.

scholarly journals Dislocation dynamics prediction of the strength of Al–Cu alloys containing shearable θ′′ precipitates

2021 ◽  
Vol 151 ◽  
pp. 104375
Author(s):  
R. Santos-Güemes ◽  
L. Capolungo ◽  
J. Segurado ◽  
J. LLorca
Keyword(s):  
Dislocation Dynamics ◽  
Cu Alloys

Disorientations in dislocation structures: Formation and spatial correlation

2002 ◽  
Vol 17 (9) ◽  
pp. 2433-2441 ◽  
Author(s):  
Wolfgang Pantleon
Keyword(s):  
Plastic Deformation ◽  
Spatial Correlation ◽  
Distribution Functions ◽  
Scaling Behavior ◽  
Dislocation Dynamics ◽  
Slip Systems ◽  
Experimental Findings ◽  
Good Agreement

During plastic deformation, dislocation boundaries are formed and orientation differences across them arise. Two different causes lead to the formation of two kinds of deformation-induced boundaries: a statistical trapping of dislocations in incidental dislocation boundaries and a difference in the activation of slip systems on both sides of geometrically necessary boundaries. On the basis of these mechanisms, the occurrence of disorientations across both types of dislocation boundaries is modeled by dislocation dynamics. The resulting evolution of the disorientation angles with strain is in good agreement with experimental observations. The theoretically obtained distribution functions for the disorientation angles describe the experimental findings well and explain their scaling behavior. The model also predicts correlations between disorientations in neighboring boundaries, and evidence for their existence is presented.

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