Dislocation behavior in nickel and iron during laser shock-induced plastic deformation

Zhou, Wangfan; Ren, Xudong; Yu, Yihua; Tong, Zhaopeng; Chen, Lan

doi:10.1007/s00170-019-04822-8

Cited by 21 publications

(6 citation statements)

References 30 publications

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“…Assuming 1 mol of Ni, at T = 850 K we get c 0 = 4.96 × 10 −8 and M cl = 9.6 × 10 −16 Pa −1 s −1 . The approximate glide mobilities for Ni are in the order of 10 5 Pa −1 s −1 [76]. If applied stress is σ = 300 MPa, the time scale for glide event is 10 −14 s and for climb event is 1.7 × 10 −3 s. We find that there is a huge time-scale separation for glide and climb event as discussed by Keralavarma and co-workers [52].…”

Section: Timescale Bridgingsupporting

confidence: 65%

Interfacial dislocation network in precipitation strengthened alloys during creep: a discrete dislocation dynamics (DDD) study in three dimensions

Jogi¹,

Bhattacharyya²

2021

Modelling Simul. Mater. Sci. Eng.

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Ni-base superalloys show an intricate network of dislocations around γ′ precipitates during high-temperature low-to-intermediate stress creep. With an aim to understand the formation of this interfacial dislocation network on the surfaces of unsheared, cuboidal γ′ precipitates, we perform three-dimensional discrete dislocation dynamics simulations at constant stress in a model system containing superellipsoidal inclusions. The exponents of the superellipsoid are adjusted to fit the cuboidal shape of γ′. We use a fault-energy-based back-force model to describe interactions between dislocations and structurally inhomogeneous inclusions. The model incorporates climb of edge dislocation segments on non-glissile planes through a modified dislocation mobility law for face-centred cubic crystals. Athermal repulsive intersection cross-slip is considered for the screw segments. We systematically show the evolution of dislocation network as a function of applied stress, inter-particle spacing, and ratio of glide-to-climb mobility. We scale the simulation box and the inclusions by the same factor in order to keep the volume fraction of inclusions constant in all cases. Although the dislocation density increases with the increase in applied stress as well as inter-particle spacing, the onset of steady-state in all cases is marked by a constant mobile-to-immobile dislocation density (ρ m/ρ im) ratio. For the range of stresses and inter-particle spacings considered in this study, the steady-state ρ m/ρ im remains nearly the same. Our simulations indicate a power-law behaviour where the stress exponent n ≈ 4 suggests dislocation climb to be the rate-controlling mechanism. The simulated morphological features of the dislocation network formed on the surfaces of the inclusions at steady-state (e.g., hexagonal nets due to dislocation reactions) are similar to those observed experimentally in single-crystalline superalloys crept at high temperatures and low stresses. Moreover, we obtain a relationship between length scale associated with dislocation density and applied stress.

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Section: Timescale Bridgingsupporting

confidence: 65%

Interfacial dislocation network in precipitation strengthened alloys during creep: a discrete dislocation dynamics (DDD) study in three dimensions

Jogi¹,

Bhattacharyya²

2021

Modelling Simul. Mater. Sci. Eng.

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“…[ 26,27 ] Therefore, the smaller the SF value, the higher is the yield stress of the crystal. [ 28 ] Internal stress is an elastic force; when the internal stress exceeds the yield stress of the crystal, the crystal will deform plastically and release the internal stress. It means that the higher the yield stress of the crystal, the higher internal stress it can accommodate.…”

Section: Resultsmentioning

confidence: 99%

Experimental Investigation on the Inhomogeneities of Transverse Microstructure and Internal Stress of High‐Strength Low‐Alloy Hot‐Rolled Strip

Fei

Wang

Yang

et al. 2022

steel research int.

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Herein, the evolution of transformation in the width direction of high‐strength low‐alloy hot‐rolled strip is studied by using thermomechanical simulation, and the temperature, microstructure, and internal stress are correlated based on electron backscatter diffraction data. The temperature and time range of the transverse transformation are determined based on the thermal expansion curve. The results show that the transformation at the edge of the steel plate ends earliest and that at the plate center begins at the latest; only 31.9% austenite undergoes transformation at the plate central by the end of laminar cooling. The fraction of transformed austenite at the plate center is the least throughout the laminar cooling process. The proportion of small grains (within the grain size range of 0–4 μm), mean, and variant coefficient of grain sizes at the plate edge are 75%, 4 μm, and 1.29, respectively. In contrast, those values of the central region are 66%, 4.4 μm, and 1.05, respectively. The correlation between temperature and internal stress evolutions is established. It is demonstrated that the internal stress increases monotonically with the average transformation rate.

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“…The Ni-DC4/US hardness value was displaced above the Hall-Petch relationship (Fig. 3) due to the additional hardening effects caused by the US agitation resulting in grain refinement and an increase in dislocation density [40]. The grain size strengthening effect due to US agitation (H HP(US) ) was calculated by the difference between the base value (H HP(i) ) and the hardness value calculated by the Hall-Petch relationship (Eq.…”

Section: Strengthening Mechanismsmentioning

confidence: 99%

“…As a result of immersing the US horn directly into the bath, the cathode was exposed to direct US cavitation, causing strain rate deformation to the crystallizing metal. Zhou et al [40] showed that the dislocation density of nickel increased with strain. Thus, the strain rate deformation by the US cavitation might have caused an increase in the dislocation density, providing an added strengthening effect (H dd(US) ) to the material.…”

Section: Strengthening Mechanismsmentioning

confidence: 99%

Strengthening mechanisms and wear behavior of electrodeposited Ni–SiC nanocomposite coatings

2022

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The present paper describes the study of the synergism between the matrix microstructure and reinforcement phase in electrodeposited nanocomposite coatings. Adding hard nanoparticles into the metallic matrix leads to hardening of the coating. The effects of particle load, size and dispersion on hardening as well as their influence on metal microstructure refinement were studied. The relative contributions of strengthening factors in Ni/nano-SiC composites, namely, Hall–Petch strengthening, Orowan strengthening, enhanced dislocation density and particles incorporation, were evaluated. The production of various coatings under different stirring conditions and powders resulted in dissimilarities in the incorporation of particles. The Hall–Petch relationship for pure nickel was determined using samples produced under different current densities. Additionally, the grain refinement resulting from the particle codeposition and agitation mode were identified as influential factors in grain-size strengthening. Dislocation density strengthening was significant in electrodeposits produced using ultrasonic agitation, while it was negligible in layers produced under other conditions. Particles codeposition affected the magnitude of Orowan strengthening, resulting in cases where strengthening was negligible despite the presence of particles. The sum of contributions and the modified Clyne methods were used to calculate the hardness of the composites based on the contribution of each strengthening factor, and the calculation results were in good agreement with experimental data. The wear behavior of the composites was analyzed by pin-on-disk measurements, and the results correlated with the strengthening mechanisms. Particle size, dispersion and content increased the strengthening effects as well as the hardness and wear resistance of the coatings. Graphical abstract

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Dislocation behavior in nickel and iron during laser shock-induced plastic deformation

Cited by 21 publications

References 30 publications

Interfacial dislocation network in precipitation strengthened alloys during creep: a discrete dislocation dynamics (DDD) study in three dimensions

Interfacial dislocation network in precipitation strengthened alloys during creep: a discrete dislocation dynamics (DDD) study in three dimensions

Experimental Investigation on the Inhomogeneities of Transverse Microstructure and Internal Stress of High‐Strength Low‐Alloy Hot‐Rolled Strip

Strengthening mechanisms and wear behavior of electrodeposited Ni–SiC nanocomposite coatings

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