Dislocation arrangements in cyclically deformed Au single crystal

Li, P.; Li, S.X.; Wang, Z.G.; Zhang, Z.F.

doi:10.1016/j.msea.2010.06.040

Cited by 21 publications

(5 citation statements)

References 21 publications

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“…Besides Cu single crystals, such periodically ordered structure also appeares in the fatigued Ni, Ag and Au single crystals [13][14][15][16][17]. Then, the question is whether all the FCC pure metals can form the classical dislocation patterns by cyclic deformation.…”

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confidence: 99%

Basic criterion for the formation of self-organized dislocation patterns in fatigued FCC pure metals

Zhongguang

Zhang

2015

Sci. China Mater.

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tively proposed based on stacking fault energy (SFE).As shown in Fig. 1, PSB ladders or walls are a three-dimensional structure. PSB ladders from t he (12 − 1) plane or PSB walls from the (111) plane occupy about 10% of the PSBs by volume. The walls are 0.03-0.25 μm in thickness with a spacing of about 1.3 μm (see Fig. 2) and they consist of numerous dipoles, especially faulted dipole. The socalled faulted dipole consists of four Shockley partial dislocations and three stacking faults. Th e stair-rods lie at the ends of the stacking fault in the secondary slip plane and their relative position are thus fixed. The dipole as a whole can assume an S-or Z-shaped configuration depending on the position of the Shockley partials. In 1976, Antonopoulos et al. [11,12] pointed out that the matrix vein contained both primary edge dipole and faulted dipole, however, the PSBs were almost full of faulted dipoles, which reflected the microstructure evolution of dislocation patterns. On Based on a large number of experimental results available, it is found that not all the fatigued face-centered-cubic (FCC) pure metals can form the classical persistent slip band (PSB)-ladder structure. The formation of the regular dislocation patterns, especially the PSB ladders, follows one unified principle on the dislocation aggregation and evolution. According to the principle, a simple criterion based on stacking fault energy is proposed to judge whether or not the regular PSB ladders in different FCC pure metals can form.

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confidence: 99%

Basic criterion for the formation of self-organized dislocation patterns in fatigued FCC pure metals

Zhongguang

Zhang

2015

Sci. China Mater.

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“…A representative cubic volume cell (RCVC) with dimensions of (30000𝑏) 3 is built, with the Burgers vector, shear modulus, Poisson's ratio and SFE being 𝑏 = 2.9 Å, 𝜇 = 30 GPa, 𝜈 = 0.354, 𝛾 = 16 mJ/m 2 , respectively. [14,15] Since the RCVC is large enough, influence from outside the boundaries can be neglected. All F-R sources are located on the (111) slip plane with the 𝑥-axis ⟨ 211⟩, 𝑦-axis ⟨0 11⟩ and 𝑧-axis ⟨111⟩, respectively.…”

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confidence: 99%

Dislocation Dissociation Strongly Influences on Frank—Read Source Nucleation and Microplasticy of Materials with Low Stacking Fault Energy

Huang

Zhu

2014

Chinese Phys. Lett.

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The influence of dislocation dissociation on the evolution of Frank-Read (F-R) sources is studied using a threedimensional discrete dislocation dynamics simulation (3D-DDD). The classical Orowan nucleation stress and recently proposed Benzerga nucleation time models for F-R sources are improved. This work shows that it is necessary to introduce the dislocation dissociation scheme into 3D-DDD simulation, especially for simulations on micro-plasticity of small sized materials with low stacking fault energy.

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“…It is worth noting however that these fcc metals and alloys (Ag, Cu and Au) show significant anisotropy in the single crystal form and therefore when the polycrystalline shear modulus is used as a parameter, the physical origin of G/γ sf is not immediately evident . Along these lines, the elastic modulus for polycrystalline MP35N is reported to be 230 GPa [7] and its SFE is ~25 mJm -2 [2] and therefore, assuming G ~0.4E, G/γ sf is ~3.7 x10 12 m -1 which is outside of the range identified in [33,34] for Ni, Ag, Au and Cu where PSBs were observed, while this value is similar to that reported for Cu-10% Al [34] where no PSBs were observed. Therefore, it appears that the observation of PSBs in Figure 10c in this study cannot be satisfactorily explained using the above arguments.…”

Section: Discussionmentioning

confidence: 93%

“…The dislocation structure that evolves during cyclic loading in various fcc metals and alloys has been examined; Li et al [11,33,34] postulate, based on experimental results on single crystals of Ni, Cu, Au and Ag, that two parameters, τ s /G and G/γ sf , play important roles in determining the evolution of dislocation patterns. Here, τ s is the saturation resolved shear stress, G is the polycrystalline shear modulus and γ sf is the stacking fault energy.…”

Section: Discussionmentioning

confidence: 99%