High strength and high ductility of electrodeposited nanocrystalline Ni with a broad grain size distribution

Shen, Xixun; Lian, Jianshe; Jiang, Zhonghao; Jiang, Qing

doi:10.1016/j.msea.2007.10.018

Cited by 73 publications

(39 citation statements)

References 38 publications

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“…2,5,6,[41][42][43][44][45][46][47] Earlier work on the yield strength of nc nickel has been most derived from the hardness measurements due to undersized sample dimensions, and the facts that many samples showed nearly brittle behavior and low strength in tension. To discuss the strength of nc nickel, Fig.…”

Section: Discussion a Strength And Strain Rate Sensitivitymentioning

confidence: 99%

“…This observation supports the GB affected zone model and some prior experiments; 7 but contradictory findings have been reported. 2,6 Table 3 gathers all the tensile properties of nc cobalt and nc nickel measured from our experiments, after the corrections of strength values from grain growth.…”

Section: B Tensile Characteristicsmentioning

confidence: 99%

“…The spread of data becomes even more problematic when the tensile elongation to failure (ε tef ) of nc materials is compared; e.g., for nc nickel with d~20-30 nm, the reported ε tef value ranges as much as from 0.01 to 0.11. 2,3,[5][6][7] These drastic variations of tensile properties, yet in a monolithic fcc nc metal such as nickel, not only make it difficult to substantiate computer models from experiments, but also strongly suggest that there remains a pressing need to investigate possible variables and mechanisms controlling the tensile property of nc materials. The tensile ductility (i.e., ε tef ) of nc metals, in particular, is poorly understood, as it is intricately related to the necking and fracture process of nc materials, and can hardly be addressed by a single existing model.…”

Section: Introductionmentioning

confidence: 99%

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Controlling factors in tensile deformation of nanocrystalline cobalt and nickel

et al. 2012

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In an effort to understand and enhance the tensile ductility of truly nanocrystalline metals, we have investigated and compared the mechanical behavior, especially the tensile behavior, of hcp nanocrystalline cobalt (~20 nm) and fcc nanocrystalline nickel (~28 nm). Although both materials exhibit obvious plasticity in tension, their uniform tensile ductility, tensile elongationto-failure, and fracture behavior are drastically different. In-situ synchrotron x-ray diffraction and ultra-small angle x-ray scattering reveal distinct deformation disparity in terms of residual strain development, texture evolution, nanovoid formation, and subsequent strain hardening and strain rate hardening behavior. The dependence of tensile property on the strain rate and temperature is examined and discussed. Factors that influence the strength and ductility of nanocrystalline metals are considered and prioritized according to the current findings. A new Hall-petch relationship is proposed for nanocrystalline nickel.

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Section: Discussion a Strength And Strain Rate Sensitivitymentioning

confidence: 99%

Section: B Tensile Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Controlling factors in tensile deformation of nanocrystalline cobalt and nickel

et al. 2012

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“…Previously, there has been considerable research on electrodeposited nc-Ni. [14][15][16][17][18][19][20][21][22][23][24][25] Most of these investigations were used sulfate electrolyte as a fabrication process of nc-Ni. In general, electrodepositon bath based nickel sulfate lead to larger internal stress than that based nickel sulfamate in the coatings.…”

Section: Discussionmentioning

confidence: 99%

“…As a result of tensile test, the sample F exhibited higher ductility than the sample W. Moreover, the flat fracture part which was similar to fracture surface shown in brittle failure were observed in the sample W. It is considered that high internal stress which provided a warped specimen introduced a lot of defect into the sample W. In reported data, fabrication process of nc-Ni exhibited good ductility of over 5% was added some gloss agents, surfactants that acted as stress relievers. 18,[20][21][22]24,25) Therefore, internal stress is one of the important factors that have the effect on tensile property of electrodesposited nc-Ni. It is suggested that internal stress which is generated from electrodepostion was necessary to suppress on investigating tensile property of electrodeposited nc-Ni.…”

Section: Discussionmentioning

confidence: 99%

Influence of Bath Composition on Tensile Ductility in Electrodeposited Bulk Nanocrystalline Nickel

et al. 2011

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We investigated the influence of bath composition on characteristics in an electrodeposited bulk nanocrystalline Ni (nc-Ni). This study was aim to establish the fabrication process of bulk nc-Ni with good tensile property. The bulk nc-Ni was electrpdeposited from a sulfate bath and a sulfamate bath. The nc-Ni was evaluated for microstructure and mechanical properties, such as microhardness, tensile strength. As a result, bulk nc-Ni obtained from a sulfamate bath exhibited enhanced tensile property (ultimate tensile strength of 1006 MPa and ductility of 8.8%) compared to that obtained from a sulfate bath. Dimple pattern was observed in fracture surface of bulk nc-Ni obtained from a sulfamate bath. However, dimple pattern and brittle fracture surface were observed in bulk nc-Ni obtained from a sulfate bath. We consider the ductility of electrodeposited nc-Ni was influenced by internal stress generated from electrodepostion. These experiments and analyses suggest that it is important to control internal stress on fabrication of bulk nc-Ni with high tensile strength and good ductility.

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The Optimal Grain Sized Nanocrystalline Ni with High Strength and Good Ductility Fabricated by a Direct Current Electrodeposition

et al. 2008

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In the past two decades, nanocrystalline (nc) metals and alloys are known to possess some novel mechanical properties, such as high strength, superior wear resistance and possibly superplasticity at low temperature or high strain rates, [1][2][3][4][5][6][7][8] Compared to the conventional coarse-grained (CG) materials with grain size typically larger than 1 lm. However, some experiments showed that nc metals and alloys hold unexpected low ductility being generally less than a few percent, [9][10][11][12][13][14] which may obliterate their potential application as advanced structure materials. The factors that limit the ductility of nc or nanostructured (ns) materials include the artifacts from immature processing (such as inert gas condensation, ball-milling or mechanical alloying) [2,[15][16] and the mechanical instability of materials with little or no strain hardening capacity because of their low dislocation accumulation capability. [3,[17][18] Recently, by adjusting the microstructure of nc and ns materials, some researchers attained nc or ns materials with a good combination of strength and ductility. [19][20][21][22][23][24][25][26] For example, Wang et al fabricated a ns Cu with a bimodal grain size distribution of micrometer-sized grains embedded inside a matrix of ultrafine grains, by a thermomechanical treatment of the severe plastic deformation (SPD) Cu. [21] Such ns Cu holds a high tensile ductility with 65 % elongation to failure (d ETF ) and 30 % uniform elongation (d UE ), and a moderate ultimate tensile strength (r UTS ) of 400 ∼ 500 MPa. The inhomogeneous microstructure increases the ability of work hardening and leads to an increase of the tensile ductility of ns Cu. [21] Lu et al produced the high-purity Cu samples with nanoscale growth twins inside the ultrafine grains (ufg) by the pulsed electrodeposition technique. [22] This nano-scale growth twined Cu exhibited a very high yield strength (r Y ) of 900 MPa and a good d ETF of 13.5 %. The growth twins serve as effect barriers to dislocation motion and also simultaneously provide sources for dislocation nucleation, which imparts ns Cu a good ductility and electrical conductivity. Though the foregoing nanostructured metals exhibit the optimized mechanical properties and in some way can meet the need in engineering application, they, strictly speaking, don't belong to the "true" nc materials with grain size < 100 nm because their grain sizes locate between 100 nm ∼ 1 lm. In fact, what is the intrinsic mechanical property of the "true" nc metals and the relation between their mechanical properties including both strength and ductility and the grain size are still not very clear.In previous studies, most understanding and information about the mechanical properties and deformation mechanism were accumulated from different individual experiments on different nc metals or alloys with a single or a few grain sizes, fabricated by the different preparation method. Up to now a systemic experimental data is not available on study the changing trends of...

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High strength and high ductility of electrodeposited nanocrystalline Ni with a broad grain size distribution

Cited by 73 publications

References 38 publications

Controlling factors in tensile deformation of nanocrystalline cobalt and nickel

Controlling factors in tensile deformation of nanocrystalline cobalt and nickel

Influence of Bath Composition on Tensile Ductility in Electrodeposited Bulk Nanocrystalline Nickel

The Optimal Grain Sized Nanocrystalline Ni with High Strength and Good Ductility Fabricated by a Direct Current Electrodeposition

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