Journal ArticleDOI
Effect of Cd on superplastic flow in the Pb-62 wt% Sn eutectic
TLDR
In this article, a detailed investigation of the superplastic deformation of two grades of the Pb-62 Sn eutectic (where the compositions here and subsequently are in weight per cent) was conducted under identical experimental conditions of grain size (about 8 μm), temperature (390-420 K) and stress (0·1-10 MPa).Abstract:
A detailed investigation of the superplastic deformation of two grades of the Pb-62 Sn eutectic (where the compositions here and subsequently are in weight per cent) was conducted under identical experimental conditions of grain size (about 8 μm), temperature (390–420 K) and stress (0·1–10 MPa). The first grade (grade 1) is Pb-62 Sn containing 890 wt p.p.m. Cd while the second grade (grade 2) is very-high-purity Pb-62 Sn. The experimental results on grade 1 (Pb-62Sn doped with Cd) show the presence of a sigmoidal relationship between strain rate and stress. This sigmoidal behaviour exhibits firstly an intermediate-stress region (region II) which is characterized by a stress exponent n of about 1·7 and an activation energy Q similar to the activation energy Q gb anticipated for grain-boundary diffusion and secondly a low-stress region (region I), where n > 2·6 and Q > Q gb. By contrast, the experimental results on grade 2 (high-purity Pb-62 Sn) show that the characteristics of superplastic flow at...read more
Citations
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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.
Journal ArticleDOI
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.
Journal ArticleDOI
Creep and superplasticity in nanocrystalline materials: current understanding and future prospects
Farghalli A. Mohamed,Yong Li +1 more
TL;DR: A review of these studies shows that data obtained by different investigators are either not consistent in trend or too limited in scope as discussed by the authors, and it is suggested that a number of issues need to be fully addressed in order to provide a better understanding of the deformation processes which control the behavior of nc-materials.
Journal ArticleDOI
Superplastic behavior of an Al/Mg alloy at elevated temperatures
TL;DR: In this article, the superplastic properties and microstructural evolution of a 0.2% Zr and 1.6% Mn modified 5083 aluminum alloy with an initial grain size of 6.2 μm were examined at strain rates ranging from 10−5 to 10−1 s−1 in the temperature interval 500-580°C.
Journal ArticleDOI
Review: achieving superplastic properties in ultrafine-grained materials at high temperatures
TL;DR: In this article, a review examines recent results that demonstrate the occurrence of exceptional superplastic flow in a series of UFG aluminum and magnesium alloys after ECAP and HPT.
References
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Journal ArticleDOI
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.
Journal ArticleDOI
Mechanical behavior of crystalline solids at elevated temperature
Oleg D. Sherby,Peter M. Burke +1 more
TL;DR: In this paper, the mechanical behavior of crystalline solids at elevated temperatures is discussed, including the creep properties of metals, solid solutions and two phase alloys, and the properties of two-phase alloys.
Journal ArticleDOI
Superplasticity—Recent advances and future directions
Oleg D. Sherby,Jeffrey Wadsworth +1 more
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 rate controlling mechanism in superplasticity
TL;DR: In this paper, a model for superplastic deformation is proposed that is based on grain boundary sliding and is controlled by the rate of deformation of the grain interior, and a comparison is made of the proposed model and the various creep mechanisms in order to reveal the ranges of conditions over which each mechanism predominates and how the various mechanisms are related one to another.