Journal ArticleDOI
Creep at low stress levels in the superplastic Zn-22% Al eutectoid
TLDR
A sigmoidal relationship between strain rate and stress was observed in a superplastic Zn-22% Al eutectoid alloy with grain sizes in the range of 2.1-7.5 μm.About:
This article is published in Acta Metallurgica.The article was published on 1975-01-01. It has received 160 citations till now. The article focuses on the topics: Grain Boundary Sliding & Grain boundary strengthening.read more
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Twenty-five years of ultrafine-grained materials: achieving exceptional properties through grain refinement
TL;DR: In this article, an overview of the more recent developments in this field, with special emphasis on the opportunities for achieving homogeneity in the as-processed materials and on the general characteristics of the mechanical properties achieved after SPD processing.
Journal ArticleDOI
Grain-boundary sliding and its accommodation during creep and superplasticity
TL;DR: In this paper, the roles of grain-boundary sliding (GBS) and of other creep mechanisms in creep and fine-grain superplasticity are presented in relation to a model based on the division of grains into their central cores and peripheral “mantles.
Journal ArticleDOI
The mechanical properties of superplastic materials
TL;DR: The relationship between stress and strain rate is often sigmoidal in superplastic materials, with a low strain rate sensitivity at low and high strain rates (regions I and III, respectively) and a high strain rate sensitive at intermediate strain rate (region II) where the material exhibits optimal super-plasticity as discussed by the authors.
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Grain boundary sliding revisited: Developments in sliding over four decades
TL;DR: In this article, the authors reviewed the developments in grain boundary sliding over the last four decades including the procedures available for estimating the strain contributed by sliding to the total strain, ξ, and the division into Rachinger boundary sliding (GBS) in conventional creep and Lifshitz GBS in diffusion creep.
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Seventy-five years of superplasticity: historic developments and new opportunities
TL;DR: A review of the current understanding of the flow of superplastic metals and ceramics can be found in this paper, where a minor modification to the present definition of super-plasticity is proposed.
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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Diffusion-accommodated flow and superplasticity
M.F. Ashby,R. A. Verrall +1 more
TL;DR: In this article, a new mechanism for superplastic deformation is described and modelled, which differs fundamentally from Nabarro-Herring and Coble creep in a topological sense: grains switch their neighbors and do not elongate significantly.
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Steady‐State Creep through Dislocation Climb
TL;DR: In this article, a dislocation climb creep model is considered which does not require the production of immobile dislocations, and the creep equation that results from the analysis is creep rate = Aσ3sinh(Bσ1.5/kT)exp(−Q/kTs), where A and B are constants, σ is the stress, Q is the activation energy of creep and kT has its usual meaning.
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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.