Continuum dislocation theory accounting for redundant dislocations and Taylor hardening

Le, Khanh Chau; Sembiring, Pramio G.; Tran, Thanh-Hai

doi:10.1016/j.ijengsci.2016.06.001

Cited by 14 publications

(5 citation statements)

References 53 publications

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“…The threshold stress at which the excess dislocations nucleate is higher than that without redundant dislocations or Taylor hardening. 43 Then, it seems that intrinsic dislocations play a more important role than increased entropy to improve the hardness of carbide ceramics based on our results. The lowest energy dissipation and best elastic recovery of (TiZr)C can be related to the lowest density of excess dislocations generated under stress.…”

Section: Resultssupporting

confidence: 53%

“…As discussed earlier, the increased entropy induced lattice stress or chemical disorder, whereas the intrinsic dislocations would affect the growth of dislocations under stress, leading to an increase in hardness or strength. The threshold stress at which the excess dislocations nucleate is higher than that without redundant dislocations or Taylor hardening 43 . Then, it seems that intrinsic dislocations play a more important role than increased entropy to improve the hardness of carbide ceramics based on our results.…”

Section: Resultsmentioning

confidence: 51%

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High hardness (TiZr)C ceramic with dislocation networks

et al. 2022

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Raising the configurational entropy in a solid solution ceramic is regarded as a promising strategy to improve the mechanical properties of ceramics, especially when five or more elements are mixed to form so-called high-entropy ceramics. However, in this study, we report that the binary (TiZr)C solid solution ceramics can demonstrate high hardness comparable or even superior to high-entropy ceramics. Followed by a carbothermal reduction synthesis of carbide powders, the bulk ceramics were synthesized by hot pressing. Via increasing the hot pressing temperature to 2200 • C, a full solid solution of equimolar (TiZr)C was obtained in contrast to phase separation at lower sintering temperatures, for example, 2000 and 2100 • C. The dislocation networks are observed in the single-phase (TiZr)C ceramic and should be the product of competition between enthalpy and entropy in a binary full solid solution. These defects finally contribute to the high nano-hardness of 41.9 ± 1.4 GPa (H) and the Vickers hardness of 22.0 ± 0.6 GPa (H V at 49 N).

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Section: Resultssupporting

confidence: 53%

Section: Resultsmentioning

confidence: 51%

High hardness (TiZr)C ceramic with dislocation networks

et al. 2022

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“…Based on the results of the stress-strain curve, it can be said that the hardening mechanism of the nickel and copper polycrystals is based on the Taylor hardening theory, which declares that shear stress increases gradually by strain rate [31,32] and there is a direct relation between the dislocations density and shear stress. However, the deformation behavior of the equimolar Cu-Ni alloy does not follow this theory.…”

Section: Stress-stain Curvementioning

confidence: 99%

Using Molecular Dynamic Simulation to Understand the Deformation Mechanism in Cu, Ni, and Equimolar Cu-Ni Polycrystalline Alloys

Yazdani

Vitry

2023

Alloys

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The grain boundaries and dislocations play an important role in understanding the deformation behavior in polycrystalline materials. In this paper, the deformation mechanism of Cu, Ni, and equimolar Cu-Ni alloy was investigated using molecular dynamic simulation. The interaction between dislocations and grain boundary motion during the deformation was monitored using the dislocation extraction algorithm. Moreover, the effect of stacking fault formation and atomic band structure on the deformation behavior was discussed. Results indicate that dislocations nucleate around the grain boundary in copper, the deformation in nickel changes from planar slip bands to wavy bands, and high density of dislocation accumulation as well as numerous kink and jog formations were observed for the equimolar Cu-Ni alloy. The highest density of the Shockley dislocation and stacking faults was formed in the equimolar Cu-Ni alloy which results in the appearance of a huge gliding stage in the stress–strain curve. The grain boundaries act as a sinking source for vacancy annihilation in Ni and Cu; however, this effect was not observed in an equimolar Cu-Ni alloy. Finally, radial distribution function was used to evaluate atom segregation in grain boundaries.

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“…The variational equation ( 15) allows one to derive the remaining governing equations. From the variation of I with respect to the displacement field u(x), we obtain the quasi-static equilibrium equation and the boundary condition [43]…”

Section: Thermodynamic Frameworkmentioning

confidence: 99%

Thermodynamic theory of dislocation/grain boundary interaction

Piao

2022

Continuum Mech. Thermodyn.

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The thermodynamic theory of dislocation/grain boundary interaction, including dislocation pileup against, absorption by, and transfer through the grain boundary, is developed for non-uniform plastic deformations in polycrystals. The case study is carried out on the boundary conditions affecting work hardening of a bicrystal subjected to plane constrained shear for three types of grain boundaries: (i) impermeable hard grain boundary, (ii) grain boundary that allows dislocation transfer without absorption, and (iii) grain boundary that absorbs dislocations and allows them to pass later.

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Continuum dislocation theory accounting for redundant dislocations and Taylor hardening

Cited by 14 publications

References 53 publications

High hardness (TiZr)C ceramic with dislocation networks

High hardness (TiZr)C ceramic with dislocation networks

Using Molecular Dynamic Simulation to Understand the Deformation Mechanism in Cu, Ni, and Equimolar Cu-Ni Polycrystalline Alloys

Thermodynamic theory of dislocation/grain boundary interaction

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