Journal ArticleDOI
Fracture processes in superplastic flow
TLDR
There are four distinct types of fracture in superplastic materials: failure by quasistable plastic flow, failure by necking, cavitation failure, and quasibrittle failure as discussed by the authors.Abstract:
There are four distinct types of fracture in superplastic materials: failure by quasistable plastic flow, failure by necking, cavitation failure, and quasibrittle failure. The characteristics of these four types are described with reference to experimental examples. Maximum elongation occurs in a superplastic material when it pulls out to a fine wire in quasi stable flow. It is demonstrated that there are two basic requirements for this type of flow: (a) a suppression of localized (but not diffuse) necking, and (b) a suppression of significant cavity interlinkage (but not necessarily of cavity nucleation and growth).read more
Citations
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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 refinement and superplastic flow in an aluminum alloy processed by high-pressure torsion
Sergey V. Dobatkin,Elena N. Bastarache,Genki Sakai,Takeshi Fujita,Zenji Horita,Terence G. Langdon +5 more
TL;DR: In this article, high-pressure torsion (HPT) was used to refine Al-3% Mg-0.2% Sc alloy to refine the grain size to ∼ 0.15mm.
Journal ArticleDOI
Developing superplasticity in a magnesium alloy through a combination of extrusion and ECAP
TL;DR: In this paper, a new processing procedure was applied to a cast Mg-9% Al alloy, which involves the sequential application of extrusion and equal-channel angular pressing and is designated EX-ECAP.
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
Using ECAP to achieve grain refinement, precipitate fragmentation and high strain rate superplasticity in a spray-cast aluminum alloy
TL;DR: In this article, an aluminum 7034 alloy was processed by equal-channel angular pressing (ECAP) at 473 K to produce an ultrafine grain size of ~0.3 μm.
References
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Journal ArticleDOI
Theory of the tensile test
TL;DR: In this paper, the tensile test is re-examined with special attention to the influence of strain rate sensitivity of the flow stress, and explicit formulae are deduced for the measured variables of the test in terms of the phenomenological parameters of the material.
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Influence of strain-rate sensitivity on necking under uniaxial tension
John W. Hutchinson,K. W. Neale +1 more
TL;DR: In this article, the influence of material strain-rate dependence on necking retardation is studied and a nonlinear analysis for long-wavelength nonuniformities does reproduce the essential details of the phenomenon.
Journal ArticleDOI
Factors influencing ductility in the superplastic Zn-22 Pct Al eutectoid
TL;DR: In this article, the maximum attainable ductility in the superplastic Zn-22 pct Al eutectoid depends critically on the imposed strain rate, the testing temperature, and the initial grain size.
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Creep at low stress levels in the superplastic Zn-22% Al eutectoid
TL;DR: 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.
Journal ArticleDOI
The activation energies associated with superplastic flow
TL;DR: A sigmoidal relationship was observed between strain rate and stress in the Zn-22% Al eutectoid alloy, dividing the behavior into three distinct regions as mentioned in this paper, and the results support the suggestion that the behavior in this region arises from an intragranular creep process.