Effect of Annealing on Hardness and the Modulus of Elasticity in Bulk Nanocrystalline Nickel

Torrents, Anna; Yang, Heather; Mohamed, Farghalli A.

doi:10.1007/s11661-009-0147-0

Cited by 41 publications

(23 citation statements)

References 38 publications

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“…The filled circle points are plotted in the figure for the true stress at maximum load, · U = · UTS [1 + e U ]. Thus, · U is shown to follow a same grain size dependence with k ¾ = ³1.3 MPa·mm 1/2 as for the initial yielding behavior of the conventional grain size 58) give indication of approaching an order of magnitude increase in strength level even for fcc metals at nano-scale grain sizes. The reported value of k ¾ = ³6.2 MPa·mm 1/2 for the nanoscale nickel results were obtained as one-third of hardness, k H , measurements and can be compared with k ¾ = ³5.0 MPa·mm 1/2 for copper.…”

Section: H-p For the Fcc Casementioning

confidence: 64%

60 Years of Hall-Petch: Past to Present Nano-Scale Connections

Armstrong

2014

Mater. Trans.

195

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Pioneering research results reported in the early 1950's by E. O. Hall and N. J. Petch on iron and steel materials have led to an expanded description of the grain size dependence of the complete stressstrain behavior of a wider range of materials and including assessments of other mechanical properties such as the ductile to brittle transition behavior and the hardness of materials, particularly, of nanocrystalline materials. The dislocation pile-up model that was presented originally for the inverse square root of grain diameter dependence of material strength has endured. Most recently, the pile-up model description has been more definitely associated with the Griffith theory of achieving a critical stress concentration at the tip of a crack; and, the Hall-Petch analysis has been connected to the macro-scale description of the fracture mechanics stress intensity parameter. These topics and other "60 years of Hall-Petch" type researches are tracked over time in the present report while giving special emphasis to current order-of-magnitude strength improvements that are reported for metals with nanopolycrystalline grain diameters.

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Section: H-p For the Fcc Casementioning

confidence: 64%

60 Years of Hall-Petch: Past to Present Nano-Scale Connections

Armstrong

2014

Mater. Trans.

195

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“…Therefore, the grain size is not the sole factor in determining the microhardness (strength) of electroplating coatings. In general, the microhardness of coatings is considered to relate to grain size [36], internal stress [37], texture [38], impurities [39], and porosity [40]. Electrodeposited nanocrystalline nickel coatings by flexible friction have a (311) and/or (111) preferred orientation, and show a dense depositing microstructure without flawed cracks, which is different from the electrodeposited coarse-grained nickel coating without flexible friction.…”

Section: Strengthening Of the Electrodeposited Nickel Coatings By Flementioning

confidence: 99%

Electrodeposition of nanocrystalline nickel assisted by flexible friction from an additive-free Watts bath

Hu²,

Wang³

et al. 2015

Surface and Coatings Technology

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“…A modified 0.66 power-exponent for the inverse size dependence was obtained. Otherwise, an order-of-magnitude increase in strength level occurs also for nanopolycrystal fcc metals, as well, as demonstrated in the log/log plot of Figure 2 that has been compiled from reported measurements made on aluminum, nickel and copper materials [28][29][30][31][32][33]. …”

Section: Nanopolycrystal Fcc Metalsmentioning

confidence: 75%

Crystal Engineering for Mechanical Strength at Nano-Scale Dimensions

Armstrong¹

2017

Crystals

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Abstract:The mechanical strengths of nano-scale individual crystal or nanopolycrystalline metals, and other dimensionally-related materials are increased by an order of magnitude or more as compared to those values measured at conventional crystal or polycrystal grain dimensions. An explanation for the result is attributed to the constraint provided at the surface of the crystals or, more importantly, at interfacial boundaries within or between crystals. The effect is most often described in terms either of two size dependencies: an inverse dependence on crystal size because of single dislocation behavior or, within a polycrystalline material, in terms of a reciprocal square root of grain size dependence, designated as a Hall-Petch relationship for the researchers first pointing to the effect for steel and who provided an enduring dislocation pile-up interpretation for the relationship. The current report provides an updated description of such strength properties for iron and steel materials, and describes applications of the relationship to a wider range of materials, including non-ferrous metals, nano-twinned, polyphase, and composite materials. At limiting small nm grain sizes, there is a generally minor strength reversal that is accompanied by an additional order-of-magnitude elevation of an increased strength dependence on deformation rate, thus giving an important emphasis to the strain rate sensitivity property of materials at nano-scale dimensions.

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Effect of Annealing on Hardness and the Modulus of Elasticity in Bulk Nanocrystalline Nickel

Cited by 41 publications

References 38 publications

60 Years of Hall-Petch: Past to Present Nano-Scale Connections

60 Years of Hall-Petch: Past to Present Nano-Scale Connections

Electrodeposition of nanocrystalline nickel assisted by flexible friction from an additive-free Watts bath

Crystal Engineering for Mechanical Strength at Nano-Scale Dimensions

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