Influence of the yttrium segregation at grain boundaries in the superplasticity of yttria tetragonal zirconia polycrystals

Domínguez‐Rodríguez, Arturo; Gómez-Garcı́a, Diego; Lorenzo-Martín, Cinta; Muñoz-Bernabé, A.

doi:10.1016/s0955-2219(03)00312-1

Cited by 17 publications

(12 citation statements)

References 26 publications

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“…Details about how the segregation can influence the superplasticity in YTZP are found in references. [21][22][23] A theoretical prediction for the temperature and grain size dependence is made, and a theoretical expression is achieved 22,23 :…”

Section: Yttrium Segregation At Grain Boundariesmentioning

confidence: 99%

A critical assessment of the dislocation-driven model for superplasticity in yttria tetragonal zirconia polycrystals

Domínguez‐Rodríguez

Gómez-Garcı́a

Castillo-Rodríguez

2008

Journal of the European Ceramic Society

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Section: Yttrium Segregation At Grain Boundariesmentioning

confidence: 99%

A critical assessment of the dislocation-driven model for superplasticity in yttria tetragonal zirconia polycrystals

Domínguez‐Rodríguez

Gómez-Garcı́a

Castillo-Rodríguez

2008

Journal of the European Ceramic Society

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“…Although ceramics have high strength and hardness together with excellent thermal‐chemical stability, their brittleness at low temperatures restricts their use as structural materials . Since superplasticity was discovered in yttria‐stabilized tetragonal Zr 2 O polycrystals (YSZP), many efforts have been devoted to study this system, where grain‐boundary sliding (GBS) is recognized as being the primary deformation mechanism responsible for the high‐temperature superplastic behavior accommodated by cationic diffusion throughout the lattice . Extensive high‐temperature creep data are available in the literature, where experimental data are analyzed using the standard phenomenological creep equation:

\dot{normalε} = A \frac{σ^{n}}{d^{p}} exp (- \frac{Q}{K T})

being A a stress and temperature‐independent term reflecting the dependence of the strain rate on the microstructural features of the material (composition, amount, and physical properties of glassy phases, grain morphology, etc.…”

Section: Introductionmentioning

confidence: 99%

High‐Temperature Deformation Mechanisms in Monolithic 3YTZP and 3YTZP Containing Single‐Walled Carbon Nanotubes

2015

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Monolithic 3YTZP and 3YTZP containing 2.5 vol% of single‐walled carbon nanotubes (SWCNT) were fabricated by Spark Plasma Sintering (SPS) at 1250°C. Microstructural characterization of the as‐fabricated 3YTZP/SWCNTs composite shows a homogeneous CNTs dispersion throughout the ceramic matrix. The specimens have been crept at temperatures between 1100°C and 1200°C in order to investigate the influence of the SWCNTs addition on high‐temperature deformation mechanisms in zirconia. Slightly higher stress exponent values are found for 3YTZP/SWCNTs nanocomposites (n~2.5) compared to monolithic 3YTZP (n~2.0). However, the activation energy in 3YTZP (Q = 715 ± 60 kJ/mol) experiences a reduction of about 25% by the addition of 2.5 vol% of SWCNTs (Q = 540 ± 40 kJ/mol). Scanning electron microscopy studies indicate that there is no microstructural evolution in crept specimens, and Raman spectroscopy measurements show that SWCNTs preserved their integrity during the creep tests. All these results seem to indicate that the high‐temperature deformation mechanism is grain‐boundary sliding (GBS) accommodated by grain‐boundary diffusion, which is influenced by yttrium segregation and the presence of SWCNTs at the grain boundary.

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“…As was shown previously, 27,42 the resultant threshold stress because of this segregation, can be written as: where w is the thickness of the intermediate layer between grains. In the same way, as has been shown in Gómez‐García et al ., 27 the effective diffusion coefficient will be affected by this segregation according to: where z D is the effective charge of the diffusing species, and e the electron charge.…”

Section: Discussionmentioning

confidence: 90%

“…The electric field associated with cation segregation will affect the grain‐boundary sliding and consequently, the strain and the threshold stress as stated in 28,42 At the same time, the strain rate will also be affected through the cation effective diffusion coefficient that controls superplasticity (via ) provided the grain size is below a critical value 27 …”

Section: Discussionmentioning

confidence: 99%

Experimental Assessment of Plasticity of Nanocrystalline 1.7 mol% Yttria Tetragonal Zirconia Polycrystals

Gutiérrez‐Mora

Gómez-Garcı́a

Jiménez–Melendo

et al. 2005

Journal of the American Ceramic Society

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High temperature mechanical behavior of nanocrystalline 1.7 mol% (3 wt%) yttria tetragonal zirconia polycrystals (nc‐YTZP) was characterized by compression creep tests. The hot isostatically pressed nc‐YTZP with mean grain size of 120 nm was subjected to grain growth to obtain grain sizes in the range of 120–310 nm. Direct measurements of the creep parameters were performed in the temperature range 1150°–1300°C and stress range 5–400 MPa. The strain rates at 1150°C ranged between 2 × 10−7 and 9 × 10−5 s−1 when increasing the stress from 15 to 400 MPa. Values of the stress exponent, n=2.0±0.3, and the activation energy, Q=630±40 kJ/mol, were obtained for all test conditions. A value of the grain size exponent, p=1.5±0.3, was obtained at 1150°C in the stress range studied. Detailed microstructural observations revealed the absence of glassy phase at the grain boundaries. The creep parameters were compared with those from the literature, and the results were discussed in terms of the model recently developed by the authors, with a reasonable agreement.

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Influence of the yttrium segregation at grain boundaries in the superplasticity of yttria tetragonal zirconia polycrystals

Cited by 17 publications

References 26 publications

A critical assessment of the dislocation-driven model for superplasticity in yttria tetragonal zirconia polycrystals

A critical assessment of the dislocation-driven model for superplasticity in yttria tetragonal zirconia polycrystals

High‐Temperature Deformation Mechanisms in Monolithic 3YTZP and 3YTZP Containing Single‐Walled Carbon Nanotubes

Experimental Assessment of Plasticity of Nanocrystalline 1.7 mol% Yttria Tetragonal Zirconia Polycrystals

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