Young's modulus of nanocrystalline Fe measured by nanoindentation

Fougere, G.E.; Riester, L.; Ferber, M. K.; Weertman, J.; Siegel, R.W.

doi:10.1016/0921-5093(95)09927-1

Cited by 132 publications

(68 citation statements)

References 20 publications

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“…As seen in Table I, it was observed that both the elastic modulus and the hardness of nanocrystalline YSZ coatings were smaller than values for bulk YSZ. Similar behavior has been observed previously for nanocrystalline ceramics 15 and metals, 16 and has been shown to correlate with the presence of porosity in samples. The observed reductions in Young's moduli are commensurate with expectations based on ϳ10% porosity, 17 especially if the pores are concentrated on the grain boundaries rather than randomly distributed.…”

supporting

confidence: 87%

Grain-size-dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia films grown by metal-organic chemical vapor deposition

Soyez¹,

Eastman²,

Thompson³

et al. 2000

Applied Physics Letters

177

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A grain-size-dependent reduction in the room-temperature thermal conductivity of nanocrystalline yttria-stabilized zirconia is reported for the first time. Films were grown by metal-organic chemical vapor deposition with controlled grain sizes from 10 to 100 nm. For grain sizes smaller than approximately 30 nm, a substantial reduction in thermal conductivity was observed, reaching a value of less than one-third the bulk value at the smallest grain sizes measured. The observed behavior is consistent with expectations based on an estimation of the phonon mean-free path in zirconia. © 2000 American Institute of Physics. ͓S0003-6951͑00͒05034-8͔The efficiency of gas turbine engines is dictated by the maximum sustained operating temperature of their typically Ni-or Co-based alloy turbine rotors. The development of new, higher temperature, high-strength, lightweight alloys is desirable. 1 However, recent studies have concluded that significant near-term progress in increasing turbine engine operating temperatures is more likely to come from the development of improved thermal barrier coatings ͑TBCs͒, typically yttria-stabilized zirconia ͑YSZ͒, than from the design of new alloys. 2 New processing techniques that result in TBC microstructures with lower thermal conductivity could lead either to higher operating temperatures of turbine engines, resulting in greater efficiency, or thinner coatings for the same operating temperature, which would reduce overall weight. Nanocrystalline YSZ coatings are of interest because they offer the possibility of lowering thermal conductivity, and may also provide additional benefits for TBC applications because of the possibility of improved toughness and ductility compared to that of coarser-grained ceramics. 3,4 The low thermal conductivity of YSZ ͑ϳ2.3 W/mK for high-density, polycrystalline material with a yttria-content of 10 mol. % at 20°C 5 ͒ is due primarily to phonon scattering by vacancies on the material's highly defective oxygen sublattice. 6 The potential for reduced thermal conductivity in nanocrystalline coatings arises from the predicted enhanced phonon scattering due to the presence of numerous closely spaced grain boundaries. For example, Klemens and Gell 6 have theoretically predicted that the room temperature thermal conductivity of 10 nm grain-sized YSZ containing 7 wt. % Y 2 O 3 will be decreased more than 50% compared to 1 m grain-sized YSZ of the same composition. The goal of the present study was to experimentally determine the effect of grain size on the room-temperature thermal conductivity of YSZ, thus contributing to the fundamental understanding of grain-size-dependent phonon scattering processes.Nanocrystalline YSZ films were grown by metal-organic chemical vapor deposition ͑MOCVD͒ using a low-pressure, horizontal, cold-walled deposition system. Yttrium b-diketonate ͓Y͑thd͒ 3 ͔ and zirconium t-butoxide ͓ZrOC͑CH 3 ͒ 4 ͔ 7 were chosen as precursor materials. Highpurity nitrogen was used as the precursor carrier gas. The precursors were mixed with high-purity ...

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supporting

confidence: 87%

Grain-size-dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia films grown by metal-organic chemical vapor deposition

Soyez¹,

Eastman²,

Thompson³

et al. 2000

Applied Physics Letters

177

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“…2. The reduced modulus E is in the range 130 to 170 GPa, similar to that of a dense iron oxide [32]. In contrast to the modulus, the hardness distribution shows a significantly wider range of reduced H that extends over a distance of about 1.5-1.75 m from either side of the GB.…”

Section: Accepted Manuscriptmentioning

confidence: 79%

Nanoindentation study of corrosion-induced grain boundary degradation in a pipeline steel

Yavas

Mishra

Alshehri

et al. 2018

Electrochemistry Communications

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High-strength low-alloy steels used for oil and gas pipelines are vulnerable to intergranular stress corrosion cracking in moderately alkaline soils. The mechanism of corrosion-induced embrittlement under such conditions is not yet understood. Nanoindentation was used to detect localized degradation of mechanical properties near internal grain boundaries of X-70 steel undergoing intergranular corrosion at active dissolution potentials at pH 8.2. The measurements identified a one-micron thick mechanically-degraded layer with 25% reduced hardness near corroded grain boundaries. It is suggested that the corrosion process may introduce an active softening agent, possibly non-equilibrium lattice vacancies generated by oxidation. KeywordsIntergranular corrosion, Dissolution-induced degradation, Stress corrosion cracking, Grain boundary softening, Nanoindentation Disciplines Aerodynamics and Fluid Mechanics | Aerospace Engineering | Nanoscience and Nanotechnology | Structures and Materials CommentsThis is a manuscript of an article published as Yavas, Denizhan, Pratyush Mishra, Abdullah Alshehri, Pranav Shrotriya, Kurt R. Hebert, and Ashraf F. Bastawros. "Nanoindentation study of corrosion-induced grain boundary degradation in a pipeline steel." Electrochemistry Communications 88 (2018) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D MA N U S C R I P T AbstractHigh-strength low-alloy steels used for oil and gas pipelines are vulnerable to intergranular stress corrosion cracking in moderately alkaline soils. The mechanism of corrosion-induced embrittlement under such conditions is not yet understood. Nanoindentation was used to detect localized degradation of mechanical properties near internal grain boundaries of X-70 steel undergoing intergranular corrosion at active dissolution potentials at pH 8.2. The measurements identified a one-micron thick mechanicallydegraded layer with 25% reduced hardness near corroded grain boundaries. It is suggested that the corrosion process may introduce an active softening agent, possibly non-equilibrium lattice vacancies generated by oxidation.

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“…It is also probable that the results obtained in the present experiments are associated with the increased number of grain boundaries in the material volume and their elastic deformation. It may also be due to the technological defects, such as micro-cracks and pores [20,21]. However in our experiments this factor did not influence the value of E since the three-axial compressive stresses that act during HE eliminated the possibility of cracking.…”

Section: Resultsmentioning

confidence: 68%

Mechanical properties of titanium processed by hydrostatic extrusion

Topolski¹,

Garbacz²,

Wieciński³

et al. 2012

Archives of Metallurgy and Materials

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The mechanical properties of titanium Grade 2 subjected to the hydrostatic extrusion technique (HE) were investigated. The hydrostatic extrusion technique is a method which refines the titanium grains to a nano-metric size.Compared with coarse grained titanium (CG-Ti), nanocrystalline titanium (NC-Ti) is characterized by a much higher yield stress, tensile strength and microhardness. The yield stress of NC-Ti determined in tensile tests is higher than that measured in compression test. The Young modulus of NC-Ti is slightly lower than that of CG-Ti.Keywords: severe plastic deformation (SPD), nanocrystalline titanium, hydrostatic extrusion (HE), mechanical properties, nanocrystalline structure Przedmiot badań stanowiły właściwości mechaniczne tytanu Grade 2 poddanego wyciskaniu hydrostatycznemu. Technika wyciskania hydrostatycznego jest metodą, która umożliwia rozdrobnienie ziarna tytanu do wielkości nano-metrycznej.W porównaniu z tytanem gruboziarnistym (CG-Ti), tytan nanokrystaliczny (NC-Ti) charakteryzuje się o wiele wyższą granicą plastyczności, wytrzymałością na rozciąganie oraz mikrotwardością. Granica plastyczności NC-Ti wyznaczona podczas testów rozciągania jest wyższa niż granica plastyczności wyznaczona w testach ściskania. Natomiast moduł Young'a nanokrystalicznego tytanu jest nieznacznie mniejszy niż moduł tytanu gruboziarnistego.

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Young's modulus of nanocrystalline Fe measured by nanoindentation

Cited by 132 publications

References 20 publications

Grain-size-dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia films grown by metal-organic chemical vapor deposition

Grain-size-dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia films grown by metal-organic chemical vapor deposition

Nanoindentation study of corrosion-induced grain boundary degradation in a pipeline steel

Mechanical properties of titanium processed by hydrostatic extrusion

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