Critical examination of strain-rate sensitivity measurement by nanoindentation methods: Application to severely deformed niobium

Alkorta, Jon; Martı́nez-Esnaola, J.M.; Sevillano, J. Gil

doi:10.1016/j.actamat.2007.10.039

Cited by 106 publications

(45 citation statements)

References 34 publications

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“…Alkorta et al 17 also used an indentation strain-rate jump technique to examine the SRS in UFG niobium. They compared nanoindentation creep experiments with nanoindentation jump experiments for different strain-rate levels.…”

Section: Introductionmentioning

confidence: 99%

Nanoindentation strain-rate jump tests for determining the local strain-rate sensitivity in nanocrystalline Ni and ultrafine-grained Al

et al. 2011

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A nanoindentation strain-rate jump technique has been developed for determining the local strainrate sensitivity (SRS) of nanocrystalline and ultrafine-grained (UFG) materials. The results of the new method are compared to conventional constant strain-rate nanoindentation experiments, macroscopic compression tests, and finite element modeling (FEM) simulations. The FEM simulations showed that nanoindentation tests should yield a similar SRS as uniaxial testing and generally a good agreement is found between nanoindentation strain-rate jump experiments and compression tests. However, a higher SRS is found in constant indentation strain-rate tests, which could be caused by the long indentation times required for tests at low indentation strain rates. The nanoindentation strain-rate jump technique thus offers the possibility to use single indentations for determining the SRS at low strain rates with strongly reduced testing times. For UFG-Al, extremely fine-grained regions around a bond layer exhibit a substantial higher SRS than bulk material.

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Section: Introductionmentioning

confidence: 99%

Nanoindentation strain-rate jump tests for determining the local strain-rate sensitivity in nanocrystalline Ni and ultrafine-grained Al

et al. 2011

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“…However, nanoindentation testing is a useful tool for studying these effects on a local scale, allowing a detailed localized analysis of the deformation processes. 7 Besides focusing on the local determination of the strain-rate sensitivity, [8][9][10][11] the development of reliable nanoindentation creep experiments has gained much attention over the last decades. In literature, references can be found relating to studies of different indentation procedures concerning the relationship between indentation strain-rate and hardness.…”

Section: Introductionmentioning

confidence: 99%

An improved long-term nanoindentation creep testing approach for studying the local deformation processes in nanocrystalline metals at room and elevated temperatures

et al. 2013

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The strain-rate sensitivity of ultrafine-grained aluminum (Al) and nanocrystalline nickel (Ni) is studied with an improved nanoindentation creep method. Using the dynamic contact stiffness thermal drift influences can be minimized and reliable creep data can be obtained from nanoindentation creep experiments even at enhanced temperatures and up to 10 h. For face-centered cubic (fcc) metals it was found that the creep behavior is strongly influenced by the microstructure, as nanocrystalline (nc) as well as ultrafine-grained (ufg) samples show lower stress exponents when compared with their coarse-grained (cg) counterparts. The indentation creep behavior resembles a power-law behavior with stress exponents n being ; 20 at room temperature. For higher temperatures the stress exponents of ufg-Al and nc-Ni decrease down to n ; 5. These locally determined stress exponents are similar to the macroscopic exponents, indicating that similar deformation mechanisms are acting during indentation and macroscopic deformation. Grain boundary sliding found around the residual indentations is related to the motion of unconstrained surface grains.

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“…Recently, depth sensing nanoindentation technique is being used as an effective technique for the understanding of elastoplastic behavior of PDCs at small length scales. [7][8][9] Upon indentation these polymer derived ceramic (PDC) materials were observed to undergo plastic deformation owing to the large hydrostatic pressure under the indenter tip. 10 During constant load holding segment a change in the indentation depth is commonly observed in most of the material systems, which is referred to as the indentation creep at room temperature.…”

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confidence: 99%

Room temperature strain rate sensitivity in precursor derived HfO2/Si-C-N(O) ceramic nanocomposites

Sujith

Kumar

2014

AIP Advances

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Investigation on the room temperature strain rate sensitivity using depth sensing nanoindentation is carried out on precursor derived HfO2/Si-C-N(O) ceramic nanocomposite sintered using pulsed electric current sintering. Using constant load method the strain rate sensitivity values are estimated. Lower strain rate sensitivity of ∼ 3.7 × 10−3 is observed and the limited strain rate sensitivity of these ceramic nanocomposites is explained in terms of cluster model. It is concluded that presence of amorphous Si-C-N(O) clusters are responsible for the limited flowability in these ceramics.

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Critical examination of strain-rate sensitivity measurement by nanoindentation methods: Application to severely deformed niobium

Cited by 106 publications

References 34 publications

Nanoindentation strain-rate jump tests for determining the local strain-rate sensitivity in nanocrystalline Ni and ultrafine-grained Al

Nanoindentation strain-rate jump tests for determining the local strain-rate sensitivity in nanocrystalline Ni and ultrafine-grained Al

An improved long-term nanoindentation creep testing approach for studying the local deformation processes in nanocrystalline metals at room and elevated temperatures

Room temperature strain rate sensitivity in precursor derived HfO2/Si-C-N(O) ceramic nanocomposites

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