HYDROGEN-DISLOCATION INTERACTIONS AND INTRINSIC DISLOCATION RELAXATION IN NIOBIUM

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-73-C5-78 ◽  
Author(s):  
M. Maul ◽  
H. Schultz
Keyword(s):  
Dislocation Interactions

Observations of dislocation interactions with recrystallized grain boundaries

1988 ◽  
Vol 46 ◽  
pp. 628-629
Author(s):  
C. W. Price
Keyword(s):  
Dislocation Density ◽  
Grain Boundary ◽  
Strain Rate ◽  
Grain Boundaries ◽  
Dislocation Structure ◽  
Hot Deformation ◽  
Static Recrystallization ◽  
High Dislocation Density ◽  
High Angle ◽  
Dislocation Interactions

Little evidence exists on the interaction of individual dislocations with recrystallized grain boundaries, primarily because of the severely overlapping contrast of the high dislocation density usually present during recrystallization. Interesting evidence of such interaction, Fig. 1, was discovered during examination of some old work on the hot deformation of Al-4.64 Cu. The specimen was deformed in a programmable thermomechanical instrument at 527 C and a strain rate of 25 cm/cm/s to a strain of 0.7. Static recrystallization occurred during a post anneal of 23 s also at 527 C. The figure shows evidence of dissociation of a subboundary at an intersection with a recrystallized high-angle grain boundary. At least one set of dislocations appears to be out of contrast in Fig. 1, and a grainboundary precipitate also is visible. Unfortunately, only subgrain sizes were of interest at the time the micrograph was recorded, and no attempt was made to analyze the dislocation structure.

Amplitude-Dependent Internal Friction of Dislocation Interactions in Dual-Phase Steel

2003 ◽  
Vol 94 (4) ◽  
pp. 436-441 ◽  
Author(s):  
A. K. De ◽  
T. Waterschoot ◽  
B. C. De Cooman
Keyword(s):  
Internal Friction ◽  
Dual Phase Steel ◽  
Dual Phase ◽  
Dislocation Interactions

scholarly journals Dislocation interactions in olivine control postseismic creep of the upper mantle

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David Wallis ◽  
Lars N. Hansen ◽  
Angus J. Wilkinson ◽  
Ricardo A. Lebensohn
Keyword(s):  
Upper Mantle ◽  
Stress Transfer ◽  
Transient Creep ◽  
Slip Systems ◽  
Stress Distributions ◽  
Correlation Lengths ◽  
Mantle Viscosity ◽  
Dislocation Interactions ◽  
Different Temperatures ◽  
New Generation

AbstractChanges in stress applied to mantle rocks, such as those imposed by earthquakes, commonly induce a period of transient creep, which is often modelled based on stress transfer among slip systems due to grain interactions. However, recent experiments have demonstrated that the accumulation of stresses among dislocations is the dominant cause of strain hardening in olivine at temperatures ≤600 °C, raising the question of whether the same process contributes to transient creep at higher temperatures. Here, we demonstrate that olivine samples deformed at 25 °C or 1150–1250 °C both preserve stress heterogeneities of ~1 GPa that are imparted by dislocations and have correlation lengths of ~1 μm. The similar stress distributions formed at these different temperatures indicate that accumulation of stresses among dislocations also provides a contribution to transient creep at high temperatures. The results motivate a new generation of models that capture these intragranular processes and may refine predictions of evolving mantle viscosity over the earthquake cycle.

Experimental Analysis and Crystallographic Model of Plastic Deformation after a Change of Loading Path in Mild Steel Polycrystals

1999 ◽  
Vol 578 ◽  
Author(s):  
T. Hoc ◽  
C. Rey
Keyword(s):  
Plastic Deformation ◽  
Mild Steel ◽  
Strain Localization ◽  
Loading Path ◽  
Slip Systems ◽  
Finite Element Code ◽  
Dislocation Densities ◽  
Dislocation Interactions ◽  
Sequential Tests ◽  
Microstructural Anisotropy

AbstractStrain localization in mild steel submitted to a sequential loading paths is investigated at macroscopic, mesoscopic and microscopic scales. The experimental results demonstrate that the morphology of the localization and the nominal load-displacement curves depend on the microstructural anisotropy. A crystalline model using a finite element code is proposed. The anisotropy is described by a hardening matrix whose terms correspond to dislocation-dislocation interactions and depend on the evolution of the dislocation densities on the activated slip systems during the sequential tests. The strain localization predicted by this model fits with the experimental observation and allows us to assume that localization is correlated to the saturation on the activated slip systems.

Point defect-dislocation interactions in copper following pulsed neutron and electron irradiations

1987 ◽  
Vol 17 (3) ◽  
pp. 577-592 ◽  
Author(s):  
D M Parkin ◽  
J A Goldstone ◽  
H M Simpson ◽  
J M Hemsky
Keyword(s):  
Point Defect ◽  
Dislocation Interactions ◽  
Pulsed Neutron

scholarly journals Dislocation–grain boundary interactions: recent advances on the underlying mechanisms studied via nanoindentation testing

2021 ◽  
Author(s):  
Farhan Javaid ◽  
Habib Pouriayevali ◽  
Karsten Durst
Keyword(s):  
Grain Boundary ◽  
Mechanical Response ◽  
Displacement Curve ◽  
Ambient Conditions ◽  
Recent Advances ◽  
Slip Transfer ◽  
Depth Analysis ◽  
Dislocation Interactions ◽  
Underlying Mechanisms ◽  
Insight Into

Abstract To comprehend the mechanical behavior of a polycrystalline material, an in-depth analysis of individual grain boundary (GB) and dislocation interactions is of prime importance. In the past decade, nanoindentation emerged as a powerful tool to study the local mechanical response in the vicinity of the GB. The improved instrumentation and test protocols allow to capture various GB–dislocation interactions during the nanoindentation in the form of strain bursts on the load–displacement curve. Moreover, the interaction of the plastic zone with the GB provides important insight into the dislocation transmission effects of distinct grain boundaries. Of great importance for the analysis and interpretation of the observed effects are microstructural investigations and computational approaches. This review paper focused on recent advances in the dislocation–GB interactions and underlying mechanisms studied via nanoindentation, which includes GB pop-in phenomenon, localized grain movement under ambient conditions, and an analysis of the slip transfer mechanism using theoretical treatments and simulations. Graphical abstract

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