Using High-Pressure Torsion to Achieve Superplasticity in an AZ91 Magnesium Alloy
Roberto B. Figueiredo,Terence G. Langdon +1 more
- Vol. 10, Iss: 5, pp 681
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TLDR
In this paper, an AZ91 magnesium alloy (Mg-9%, Al-1% Zn) was processed by high pressure torsion (HPT) after solution-heat treatment.Abstract:
An AZ91 magnesium alloy (Mg-9%, Al-1% Zn) was processed by high-pressure torsion (HPT) after solution-heat treatment. Tensile tests were carried out at 423, 523, and 623 K in the strain rate range of 10−5−10−1 s−1 to evaluate the occurrence of superplasticity. Results showed that HPT processing refined the grain structure in the alloy, and grain sizes smaller than 10 µm were retained up to 623 K. Superplastic elongations were observed at low strain rates at 423 K and at all strain rates at 523 K. An examination of the experiment data showed good agreement with the theoretical prediction for grain-boundary sliding, the rate-controlling mechanism for superplasticity. Elongations in the range of 300–400% were observed at 623 K, attributed to a combination of grain-boundary-sliding and dislocation-climb mechanisms.read more
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Review on the effect of different processing techniques on the microstructure and mechanical behaviour of AZ31 Magnesium alloy
M Rakshith,P. Seenuvasaperumal +1 more
TL;DR: In this paper, the effect of different Bulk-deformation and Severe Plastic Deformation techniques on the crystal orientation and corresponding mechanical behaviours of the AZ31 alloy has been highlighted, as well as the developments made in finite element methods towards these techniques.
Journal ArticleDOI
Deformation mechanisms in ultrafine-grained metals with an emphasis on the Hall–Petch relationship and strain rate sensitivity
TL;DR: In this paper, a deformation model for high temperature grain boundary sliding was proposed to predict the relationship between strain rate, flow stress, grain size, temperature and basic material properties such as the Burgers vector modulus, the shear modulus and the grain boundary diffusion coefficient.
Journal ArticleDOI
Hot deformation behavior of an extruded AZ31 alloy doped with rare-earth elements
TL;DR: In this paper, the effect of rare-earth (RE) elements on the hot deformation behavior of an extruded Mg-3 wt% Al-1 wt % Zn (AZ31) alloy was studied.
Journal ArticleDOI
Effect of grain size on strength and strain rate sensitivity in metals
TL;DR: In this article , a physically based model for grain boundary sliding was proposed to predict the flow stress for plastic deformation for a broad range of materials using the fundamental properties of each material over a wide range of grain sizes and testing conditions.
Journal ArticleDOI
Microstructure and superplasticity of Mg-2Gd-xZn alloys processed by equal channel angular pressing
TL;DR: In this paper, a homogenous fine-grained microstructure with a grain size of 2.33μm and a high fraction of high-angle grain boundaries of 84% were formed in the Mg-2Gd-xZn (GZ23) alloy, while 4 ECAP passes were necessary to create such a structure in the other alloys.
References
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Bulk nanostructured materials from severe plastic deformation
TL;DR: In this article, the authors present methods of severe plastic deformation and formation of nanostructures, including Torsion straining under high pressure, ECA pressing, and multiple forging.
Journal ArticleDOI
Principles of equal-channel angular pressing as a processing tool for grain refinement
TL;DR: In this article, a review examines recent developments related to the use of ECAP for grain refinement including modifying conventional ECAP to increase the process efficiency and techniques for up-scaling the procedure and for the processing of hard-to-deform materials.
Journal ArticleDOI
Using high-pressure torsion for metal processing: Fundamentals and applications
TL;DR: High pressure torsion (HPT) is a well-known technique for metal forming as discussed by the authors, where samples are subjected to a compressive force and concurrent torsional straining.
Journal ArticleDOI
A unified approach to grain boundary sliding in creep and superplasticity
TL;DR: In this paper, a unified model is developed for Rachinger boundary sliding at all grain sizes, where the rate of sliding is controlled by the rates of accomodation through intragranular slip.
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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