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During HPT processing, deformation with or without dynamic recovery/ recrystallization produces a microstructure with a high dislocation density and a stored energy that is classically identified
The proposed framework is based on coupling a multiple-slip crystal plasticity formulation to three distinct dislocation densities, which pertain to statistically stored dislocations (SSDs), geometrically necessary dislocations (GNDs) and grain boundary dislocations.
Five initial dislocation densities were considered from 3.5 × 10 14 m −2 to 2.2 × 10 16 m −2. After a relaxation achieved through a conjugate gradient algorithm, a dislocation network forms
The stored energy due to cold deformation of metals is an important parameter in microstructure changes of the metals after heat treatment, since it determines the number of nuclei in recrystallization phenomenon [] has been reported that cold deformation causes the increase of dislocation density due to work hardening, and thus
Based on the parent austenite orientation reconstruction method, it is aimed to reveal the origination of high angle grain boundaries (HAGBs) and its relationship with ductility of H13 steel. The orientation relationship between martensite and parent austenite of quenched H13 samples was (123.5°, 9.3°, 192.5°), which agreed with the
Abstract. Dislocation density-based evolution formulations that are related to a heterogeneous microstructure and are physically representative of different crystalline interactions have been developed. The balance between the generation and annihilation of dislocations, through glissile and forest interactions at the slip system
Abstract. Dislocation density and crystal orientation were investigated for a set of multicrystalline silicon ingots grown in a pilot scale furnace. Both low and high dislocation density ingots were observed. The low dislocation density ingots showed a dominating orientation close to (2 1 1) in contrast to the high dislocation density ingots.
The highest recoverable energy density of 2.7 J/cm(3) under 600 kV/cm was achieved in the sample with 30 mol% ST content, which also displayed good energy-storage stability in the temperature
To address the challenge of understanding the effects of dislocations, dislocation-densities, and microstructural effects of texture and loading directions on the
Understanding the relationship between dislocation structure evolution and strain hardening behavior is crucial for the development of high-strength and high-ductility alloys. In this work, the strain hardening mechanism of S32654 super-austenitic stainless steel is studied by electron backscatter diffraction and transmission electron
Higher dislocation density leads to higher yield stress, yield strain, and elongation stress. In addition, higher temperature (600 K and 800 K) can motivate He diffusion and improve dislocation mobility, whereas higher Cr concentration (9 at.% and 14 at.%) retards both of them. Dislocation loop structure, energy and mobility of self
The variation of dislocation density with stacking fault energy (SFE) was measured in shock-deformed Cu and Cu–Al alloys. A differential scanning calorimeter (DSC) was used to measure the stored
An exothermic peak is detected between 100 °C and 200 °C in the DSC curve with an excess energy of significant dislocation storage Y. B. et al. Dislocation density evolution during high
where α is a strengthening coefficient that includes the structural arrangement of the dislocations in a pattern [] and describes the ratio of the true stress and the dislocation density. M represents the Taylor factor; G the shear modulus; and b the Burgers vector, which describes the magnitude and direction of dislocations. Equation (1) is valid if all
According to a previous study, the relationship between (σ–σ 0.2) θ and (σ–σ 0.2) is equivalent to the dislocation storage ability and dislocation density, where σ represents the true stress. In Figure 2, the ED sample indeed has a strong dislocation storage ability, while a subtle dislocation storage ability is exhibited in the TD
At the same time, the dislocation density increases from 1.47 × 10 14 m-2 to 3.46 × 10 14 m-2, which is consistent with the observed vast dislocation accumulation in TEM micrographs and TKD EBSD
As a consequence, the stored dislocation density increases in a discontinuous but progressive manner during straining, thus inducing strain hardening.
The relationship between flow stress (σ f) and dislocation density (ρ) according to Taylor [31] is given as (1) σ f = σ 0 + M α μ b ρ 1 / 2, where M is the Taylor factor, α is the constant, μ is the shear modulus, b is the Burgers vector and σ 0 is the flow stress component arising from dislocation glide resistance due to lattice
The aluminum''s high stacking fault energy (SFE) enhances the ability of cross-slip assisted dislocation motion, resulting in the formation of subgrains or
Despite the dynamic strain aging effect, stimulating the accumulation of perfect dislocations in Hadfield steel, the high dislocation density is also attributed to the high density of twin
Assuming that during homogeneous uniaxial monotonic deformation, the strain hardening is governed entirely by the microstructural changes caused by dislocations and their interactions with each other, it is the number (or density) of dislocations that determines the stored energy. The total dislocation density in the alloy is related to the
To be consistent with thermodynamics, dislocation storage implies the storage of dislocation line energy, which means that a minimum amount of work must be expended. Based on the measured initial dislocation density, it should be mentioned that the subsequent evolution of the dislocation density is calculated according to the
DDB model is used to describe the constitutive behaviors in order to reveal the relationship between dislocation density evolution and mechanical response of materials during the cutting process. The results are discussed in three different aspects, which are microstructure evolution, cutting forces variation and fracture characteristics
The relationship between the various stresses/forces. Fig. 5 shows the relationship between the five stresses/forces involved in the dislocation modeling and simulations. Since true stress/force is calculated directly from interatomic potential, it is the most accurate quantity and is used as the benchmark for other stresses/forces.
Local dislocation densities were then calculated using the relationship between the dislocation spacing in the wall and the shear strain associated with the wall γ≈θ [3]. The observation of a significantly higher dislocation density near the fibers led to the consideration that the calculated density was a good approximation of ρ G [20
The effects of grain size, source density, and misorientations on the dislocation configurational energy area density are investigated using two-dimensional
The relationship between the AE power, mobile dislocation density and plastic flow characteristic parameters - the strain hardening rate and flow stress - is derived and experimentally verified
The effects of grain size, source density, and misorientations on the dislocation configurational energy area density are investigated using two-dimensional discrete dislocation plasticity. Grain boundaries are modeled as impenetrable to dislocations. The considered grain size ranges from $$ 0.4;upmu{text{m}}^{2} $$ 0.4
After 5% deformation, a higher dislocation density is expected in austenite compared to that in ferrite. The XRD and HR-EBSD results are similar to each other, and both indicate a dislocation density that is twice as high in austenite as in ferrite for this state (approximately 1.7 × 10 14 m −2 and 0.7 × 10 14 m −2, respectively
This analysis demonstrates an intimate relationship between hardening and cell structure formation, which appears as an almost inevitable corollary to
Fig. 1 summarizes the fundamental mechanism of the proposed unified size-dependent intragranular dislocation storage model for the HP and inverse HP relations. In the case of large grains, NC shows the HP strengthening behavior because the stored intragranular dislocation density increases with decreasing d.As d reduces down
The results show a correlation between crystal strength and dislocation density for micron and sub-micron crystal sizes, and a minimum crystal strength marked
Niu et al. [80] studied the effect of process parameters on the alloy and found that the sample density exhibited a non-monotonic relationship with the volume energy density (VED).
Based on the dislocation theory, the dislocation density is related to the dislocation-stored energy (E) such that [ 9]: [ 9] Where R ˳ is the inner radius of the dislocation core (taken between
1. Introduction. The reserve limitations of fossil fuels, such as coal, petroleum, and natural gas, and their adverse impact on environmental protection become two unavoidable factors in developing an alternative, sustainable, and clean energy technology [[1], [2], [3]].Actually, solar, wind, and geothermal resources are becoming the
The mechanisms of dynamic recovery and dynamic recrystallization significantly affect the mechanical behavior and microstructure of the materials deformed at high temperatures. The modified Kocks and Mecking (K–M) model was used to assess the evolution of dislocation density of pure copper under high-temperature compression.
In other words, the storage of the system energy for the full development of dislocation tangles and walls decreases [15]. Similarly, Fig. 10 shows the mapping relationship between dislocation density distribution and shear deformation zone. Good consistency of morphology between the simulated dislocation density distribution and
One solution to this trade-off relationship lies in a strengthening strategy that not only obstructs dislocation motion, but also provides extra dislocation storage capability.
The free energy of the two-dislocation system as a function of the pinning distance is summarised in Fig. 4.The energy is higher than for two isolated dislocations of the same type as in Fig. 4 (a) and lower for two dislocations of opposite sign as shown in Fig. 4 (b). Note that the considered system is an infinite medium, hence the line energy
In the present investigation, an in-depth understanding of the relationship between dislocation kinetics and cyclic plasticity, along with the description of yield
The dislocation-charged cloud interaction energy (E int) [33,34] is expressed as: The major contribution of the present work is the relationship between dislocation density, leaching of copper ions and the antibacterial property. Acknowledgments. The authors would also like to thank. K.B. Bisal for helping in the cryo
When a dislocation reaches the TB, a long and straight dislocation segment is formed at the intersection line of the slip plane and the TB. According to the angular relationship between dislocation line and Burgers vector, as shown in Fig. 1, only two types of lattice dislocations need to be considered in FCC structure (Jin et al., 2006;
This analytical model predicts that below this critical dislocation density the strength versus dislocation density follows a power-law relationship with an exponent equal to −1.5, while above
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