Journal ArticleDOI
Creep of Doped Polycrystalline Al2O3
Tadaaki Sugita,Joseph A. Pask +1 more
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In this article, the creep behavior of polycrystalline A12O3 doped with MgO + NiO, both as-hot-pressed in graphite dies and additionally annealed, was determined for 1300° to 1470°C and for 1000 to 15,000 psi in compression.Abstract:
Creep behavior of polycrystalline A12O3 doped with MgO + NiO, both as-hot-pressed in graphite dies and additionally annealed, was determined for 1300° to 1470°C and for 1000 to 15,000 psi in compression. The deformed specimens contained intergranular separations. Creep rates were proportional to stress to the 1.1 and 1.3 powers and were independent of grain size changes occurring during creep. The suggested creep mechanism is localized plastic deformation at stress concentration points accommodated by grain-boundary separations initiated by grain-boundary sliding.read more
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Creep of ceramics: Part 1 Mechanical characteristics
Journal ArticleDOI
Creep of ceramics
TL;DR: In this article, a wide range of experimental data on the creep of ceramics was analyzed and it was shown that there is an enhanced role of diffusion creep, and in the power-law regime, Ceramics divide into two categories with stress exponents of ∼ 5 and ∼ 3, respectively.
Journal ArticleDOI
Impurity Effects on Alumina Scale Growth
TL;DR: In this article, the authors assess the possible effect of incorporated impurities on the growth rate and transport properties of Al 2 O 3 scales formed on Fe-, Ni-, and Pt-based alloys.
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Deformation of fine-grained alumina by grain boundary sliding accommodated by slip
TL;DR: In this article, the authors concluded that the dominant deformation mechanism in creep of fine-grained alumina is grain boundary sliding (GBS) accommodated by slip, which is related to the sequential steps of dislocation glide and climb.
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Creep of polycrystalline alumina, pure and doped with transition metal impurities
Paul A. Lessing,Ronald S. Gordon +1 more
TL;DR: Grain size effects were used to evaluate the relative contributions of aluminium lattice and oxygen grain boundary diffusion to the high temperature (1350 to 1550° C) steady state creep of polycrystalline alumina, pure and doped with transition metal impurities as mentioned in this paper.
References
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Journal ArticleDOI
Diffusional Viscosity of a Polycrystalline Solid
TL;DR: In this article, it is suggested that mosaic boundaries and boundaries between grains of nearly the same orientation may not serve as sources or sinks of the diffusion currents, in which case the creep rate will depend only on the configuration of grain boundaries having a sizable orientation differen...
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A Model for Boundary Diffusion Controlled Creep in Polycrystalline Materials
TL;DR: In this article, the authors discussed the mechanism of creep in polycrystalline alumina based on the differences between the lattice and boundary diffusion models and showed that the boundary diffusion model is more stable than lattice diffusion model, while the grain size dependence and the numerical constant are greater.
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Steady-State Creep of Crystals
TL;DR: In this article, an expression for the steady-state creep rate of crystals is derived for the case where dislocation climb is not rate controlling, and two rate-controlling processes are considered.
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Creep Behavior of Pore-Free Polycrystalline Aluminum Oxide
TL;DR: In this paper, the behavior of pore-free polycrystalline aluminum oxide has been studied as a function of temperature, grain size, and strain rate, and the behavior may be described byσαd2e where d is the mean grain diameter.
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Deformation Behavior of Polycrystalline Aluminum Oxide
TL;DR: The steady-state creep behavior of polycrystalline aluminum oxide from 97 to 100% dense has been examined at temperatures from 1600° to 1800°C over a range of stresses from 100 to 2000 psi under four-point transverse bending as mentioned in this paper.