Creep mechanisms of laminated alumina/zirconia-toughened alumina composites

Morales-Rodrı́guez, A.; Domínguez‐Rodríguez, Arturo; Portu, Goffredo de; Jiménez–Melendo, M.

doi:10.1016/j.jeurceramsoc.2008.09.017

Cited by 12 publications

(9 citation statements)

References 34 publications

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“…The difference in stress exponent values between these studies (n ≈ 1) and the present work (n ≈ 2) can be related with the difference in grain sizes. A transition from n = 1 towards n = 2 with decreasing grain size has been noted for other ceramic oxides 27,34 ; the critical grain size seems to be about 1 m, in agreement with the present results. Nevertheless, diffusion is the rate-limiting step in both cases; the values of Q measured in fine-and largegrained BCY (390 and 360 kJ/mol, respectively) compare very well and suggest that cation lattice diffusion is also the ratecontrolling mechanism for grain boundary sliding in the n = 2 region.…”

Section: Discussionsupporting

confidence: 92%

High-temperature mechanical behavior of polycrystalline yttrium-doped barium cerate perovskite

Vaquero-Aguilar

López-Robledo

Fernandez

et al. 2011

Journal of the European Ceramic Society

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The high-temperature mechanical properties of the mixed ionic-electronic conductor perovskite BaCe 0.95 Y 0.05 O 3−δ with average grain size of 0.40 m have been studied in compression between 1100 and 1300 • C in air at different initial strain rates. The true stress-true strain curves display an initial stress drop, followed by an extended steady-state stage. As the temperature decreases and/or the strain rate increases, there is a transition to a damage-tolerant strain-softening stage and eventually to catastrophic failure. Analysis of mechanical and microstructural data revealed that grain boundary sliding is the primary deformation mechanism. The strength drop has been correlated with the growth of ultrafine grains during deformation, already present at grain boundaries and triple grain junctions in the as-fabricated material.

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Section: Discussionsupporting

confidence: 92%

High-temperature mechanical behavior of polycrystalline yttrium-doped barium cerate perovskite

Vaquero-Aguilar

López-Robledo

Fernandez

et al. 2011

Journal of the European Ceramic Society

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“…Cai et al [ 23 ] and Sun et al [ 24 ] successfully produced layered Al 2 O 3 –CTZ FGM by traditional powder sintering and studied the optimal processing parameters to avoid cracks between the layers. Other authors [ 25 ] emphasized the study of creeping mechanisms in FGM between the layers. Salahi et al [ 21 ] fabricated dual-, triple-, and quintuple-layered Al 2 O 3 –CTZ samples with different compositions and confirmed that the hardness and fracture toughness of the multi-layer Al 2 O 3 –ZrO 2 structure was higher than those of the double-layer structure.…”

Section: Introductionmentioning

confidence: 99%

Functionally Graded Al2O3–CTZ Ceramics Fabricated by Spark Plasma Sintering

et al. 2022

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We studied the fabrication of functionally graded Al2O3–CeO2-stabilized-ZrO2 (CTZ) ceramics by spark plasma sintering. The ceramic composite exhibits a gradual change in terms of composition and porosity in the axial direction. The composition gradient was created by layering starting powders with different Al2O3 to CTZ ratios, whereas the porosity gradient was established with a large temperature difference, which was induced by an asymmetric graphite tool configuration during sintering. SEM investigations confirmed the development of a porosity gradient from the top toward the bottom side of the Al2O3–CTZ ceramic and the relative pore volume distributed in a wide range from 0.02 to 100 µm for the samples sintered in asymmetric configuration (ASY), while for the reference samples (STD), the size of pores was limited in the nanometer scale. The microhardness test exhibited a gradual change along the axis of the ASY samples, reaching 10 GPa difference between the two opposite sides of the Al2O3–CTZ ceramics without any sign of delamination or cracks between the layers. The flexural strength of the samples for both series showed an increasing tendency with higher sintering temperatures. However, the ASY samples achieved higher strength due to their lower total porosity and the newly formed elongated CeAl11O18 particles.

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“…Unfortunately, there are not enough data available in the literature for such a comparison. The diffusion and creep behavior of alumina have been widely reported [4,10,[31][32][33][48][49][50], but there are no data for EAG and ESZ monoliths. Therefore, the comparison with the isostructural oxides yttria fully-stabilized cubic zirconia (YSZ) and yttrium aluminum garnet (YAG), where Er 3+ is replaced by Y 3+ (ionic radii Er 3+ VIII = 1.004 Å and Y 3+ VIII = 1.019 Å), seems to be pertinent in this context; such a comparison is supported by the similarity of creep rates exhibited by the present composite and a three-phase AYZ sintered composite with d = 1 μm deformed in the same experimental conditions, which differ only by a factor of 2 [29].…”

Section: Creep-controlling Phase In Aez Compositesmentioning

confidence: 99%

“…Similarly, the two-phase Al 2 O 3 /yttrium aluminum garnet (YAl 5 O 12 , YAG) composites also display superior creep resistance than their single-phase counterparts [4,7,8] due to the mutual insolubility, high chemical stability and restrained grain growth of the alumina phase. Additionally, both fine-grained binary composites (grain sizes below about 1 μm) exhibit metal-like superplasticity at elevated temperatures [5,6,9,10], which contrasts strongly with the premature creep failure of monolithic alumina.…”

Section: Introductionmentioning

confidence: 99%