Superplastic Behavior in Ultrafine-Grained Materials Produced by Equal-Channel Angular Pressing

2008 ◽  
Vol 579 ◽  
pp. 29-40 ◽  
Author(s):  
Cheng Xu ◽  
Megumi Kawasaki ◽  
Roberto B. Figueiredo ◽  
Zhi Chao Duan ◽  
Terence G. Langdon
Keyword(s):  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Processing Method ◽  
Strain Rates ◽  
Bulk Materials ◽  
Superplastic Behavior ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Ultrafine Grained Materials ◽  
Aluminum And Magnesium Alloys

Equal-channel angular pressing (ECAP) is a convenient processing method for refining the grain size of bulk materials to the submicrometer level. Metallic alloys processed by ECAP often exhibit excellent superplastic characteristics including superplasticity at high strain rates. This paper summarizes recent experiments designed to evaluate the occurrence of superplasticity in representative aluminum and magnesium alloys and in the Zn-22% Al eutectoid alloy.

Extraordinary High Strain Rate Superplasticity of an Al-Mg-Sc-Zr Alloy Subjected to Equal Channel Angular Pressing

2012 ◽  
Vol 735 ◽  
pp. 295-300
Author(s):  
Elena Avtokratova ◽  
Oleg Sitdikov ◽  
Michael Markushev ◽  
Radik R. Mulyukov
Keyword(s):  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Strain Rate Range ◽  
Rate Range ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Excess Phases ◽  
Ultrafine Grained Microstructure ◽  
Zr Alloy

Unique superplastic elongations up to 4100% were achieved at 450°C in the strain rate range of 10-2-10-1s-1for Al-Mg-Sc-Zr alloy with a grain size ~1 μm processed by warm-to-hot equal channel angular pressing. Such a behavior is attributed to the synergy of complementary factors resulted in high homogeneity and stability of ultrafine-grained microstructure and superplastic flow, involving large proportion of high-angle grain boundaries, presence of dispersoids of aluminides of transition metals and negligible amount of coarse excess phases.

Microstructure and Superplasticity of an Al-Mg-Sc-Zr Alloy Processed by ECAP and Subsequent Cold Rolling

2015 ◽  
Vol 830-831 ◽  
pp. 345-349 ◽  
Author(s):  
Elena Avtokratova ◽  
Oleg Sitdikov ◽  
Oksana Mukhametdinova ◽  
Michael Markushev ◽  
S.V.S. Narayana Murty ◽  
...  
Keyword(s):  
Cold Rolling ◽  
High Strain Rate ◽  
Ambient Temperature ◽  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Strain Rates ◽  
Angular Pressing ◽  
Zr Alloy

The feasibility has been demonstrated for achieving high-strain-rate superplasticity with elongations beyond 2000% in Al-Mg-Sc-Zr alloy with the partially recrystallized structure, produced by warm equal-channel angular pressing to strain of e~3 only. Subsequent alloy ambient temperature rolling up to e~1.6 enhanced the superplastic elongations and moved the optimum of superplasticity toward the higher strain rates.

Developing High Strain Rate Superplasticity in Aluminum Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 2949-2954 ◽  
Author(s):  
Cheng Xu ◽  
Minoru Furukawa ◽  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Elevated Temperatures ◽  
High Strain ◽  
Superplastic Forming ◽  
Ultrafine Grain ◽  
Strain Rates ◽  
Cast Aluminum ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Materials Used

The conventional materials used in superplastic forming operations generally have grain sizes of ~2 µm or larger and they exhibit superplasticity at relatively low strain rates. Processing by equal-channel angular pressing (ECAP) produces materials having ultrafine-grain sizes, usually in the submicrometer range. If these ultrafine grains show reasonable stability at elevated temperatures, the alloys may exhibit a capability for achieving superplastic elongations at high strain rates. This paper examines the development of ultrafine-grained structures and superplastic ductilities in a spray-cast aluminum 7034 alloys through ECAP. The results show that ECAP is a very effective procedure for achieving grain refinement and superplasticity at rapid strain rates.

On the Influence of Mesh Size during Finite Element Simulation of Equal Channel Angular Pressing

2013 ◽  
Vol 773-774 ◽  
pp. 160-165
Author(s):  
Guan Yu Deng ◽  
C. Lu ◽  
Li Hong Su ◽  
Mao Liu ◽  
Pei Tang Wei ◽  
...  
Keyword(s):  
Finite Element ◽  
Equal Channel Angular Pressing ◽  
Texture Evolution ◽  
Mesh Size ◽  
Strain Condition ◽  
Angular Pressing ◽  
Element Simulation ◽  
Ultrafine Grained ◽  
Deformation Features ◽  
Ultrafine Grained Materials

Equal channel angular pressing (ECAP) has attracted a lot of interest due to its ability for fabrication of bulk ultrafine-grained materials. With the development of computer skills, the computer-aided methods become very important and useful in understanding the deformation mechanism of ECAP. In this study, the influence of mesh size during finite element simulations of ECAP has been examined based on the plane strain condition assumption. Four different meshes have been compared and these results indicate that Mesh 600 and Mesh 2400 fail to capture the deformation features of ECAP accurately. Large corner gaps develop in these two cases and the simulated strains are smaller than the analytical calculations. Similar results have been obtained between Mesh 6369 and Mesh 12000 and the predicted features of plastic deformation and texture evolution are consistent with the experimental results.

Processing by Equal-Channel Angular Pressing: Potential for Achieving Superplasticity

1999 ◽  
Vol 601 ◽  
Author(s):  
Minoru Furukawa ◽  
Minoru Nemoto ◽  
Zenji Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Strain ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Superplastic Deformation ◽  
Processing Method ◽  
Nanometer Scale ◽  
Strain Rates ◽  
Cross Sectional ◽  
Angular Pressing ◽  
Processing Procedure

AbstractEqual-channel angular (ECA) pressing is a processing procedure whereby a very severe plastic strain is imposed on a sample without any change in the cross-sectional dimensions of the material. This processing method leads to a substantial grain refinement, producing grains which are within the submicrometer or even the nanometer scale. This paper discusses the potential for using this method to prepare materials for superplasticity. The results demonstrate that it is possible to achieve superplastic deformation in selected materials subjected to ECA pressing and, in addition, there is the possibility of extending the superplastic region so that it occurs at very rapid strain rates.

Superplasticity of Ultrafine-Grained Aluminum Alloy Processed by ECAP and Warm Rolling

2007 ◽  
Vol 551-552 ◽  
pp. 13-20
Author(s):  
Rinat K. Islamgaliev ◽  
N.F. Yunusova ◽  
M.A. Bardinova ◽  
A.R. Kilmametov ◽  
Ruslan Valiev
Keyword(s):  
Aluminum Alloy ◽  
Room Temperature ◽  
High Strain ◽  
High Strength ◽  
Warm Rolling ◽  
Grain Structure ◽  
Strain Rates ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Equiaxed Grain

The ultrafine-grained (UFG) 1421 aluminum alloy processed by equal channel angular pressing (ECAP) has demonstrated enhanced superplasticity at low temperature and high strain rates. This UFG material was successfully rolled at temperatures of 330-370oC retaining small grain size and equiaxed grain structure. The microstructure of the UFG alloy subjected to warm rolling (WR) was studied, and the mechanical properties of the ECAP+WR samples with UFG structures were investigated. We have found that the rolled material exhibited not only the enhanced superplasticity, but also high strength at room temperature.

Low-Temperature Superplasticity in an Al-Mg-Sc Alloy Processed by ECAP

2016 ◽  
Vol 838-839 ◽  
pp. 422-427 ◽  
Author(s):  
Diana Yuzbekova ◽  
Anna Mogucheva ◽  
Rustam Kaibyshev
Keyword(s):  
Strain Rate ◽  
Rate Sensitivity ◽  
Sensitivity Coefficient ◽  
Strain Rates ◽  
Maximum Elongation ◽  
Superplastic Behavior ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Average Size

The ultrafine grained structure of an AA5024 with an average size of ∼0.7 μm was produced by equal-channel angular pressing (ECAP) at 300°C with a total strain of ~12. Superplastic behavior of this alloy was examined in the temperature interval 175 - 300°C at strain rates ranging from 10-4 to 10-1 s-1. The maximum elongation-to-failure of ~1200% with the corresponding strain rate sensitivity coefficient, m, of ∼0.49 was attained at a temperature of 275°C and a strain rate of 5.6×10–3s–1. At 175°C (~0.53Tm, where Tm is the melting point), the elongation-to-failure of ~370% with the m value of ~0.3 was found at ε̇=1.4×10–4 s–1.

Effect of Mg Content on High Strain Rate Superplasticity of Al-Mg-Sc-Zr Alloys Subjected to Equal-Channel Angular Pressing

2012 ◽  
Vol 735 ◽  
pp. 265-270 ◽  
Author(s):  
Rustam Kaibyshev ◽  
Daria Zhemchuzhnikova ◽  
Anna Mogucheva
Keyword(s):  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Tensile Tests ◽  
Chemical Compositions ◽  
Strain Rates ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Mg Content ◽  
Very High ◽  
Zr Alloys

Aluminium alloys with a chemical compositions of Al–5.8%Mg–0.52%Mn–0.2%Sc–0.07%Zr–0.16%Fe-0.1%Si and Al-5.4%Mg-0.34%Mn-0.2%Sc-0.07%Zr-0.07%Fe-0.02Si (in weight %), denoted as 1570 and 1570C, respectively, were processed by equal-channel angular pressing (ECAP) at 300°C up to strain ε~12. Extensive grain refinement provided the formation of fully recrystallized structure with the average grain sizes of 0.7 and 0.6 μm, respectively. Tensile tests were carried out in the temperature interval 200–550oC at strain rates ranging from 10-4 to 10-1 s-1. Very high tensile elongations (>1000%) were achieved in the both alloys at T350oC and strain rates higher than 10-3 s-1.

Superplastic Behavior of As-Equal Channel Angular Pressed 5083 Al and 5083 Al-0.2 Sc Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 2937-2940 ◽  
Author(s):  
Kyung Tae Park ◽  
Chong Soo Lee ◽  
Dong Hyuk Shin
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Al Alloy ◽  
Superplastic Behavior ◽  
Angular Pressing ◽  
Rate Region ◽  
Ultrafine Grained ◽  
Order Of Magnitude ◽  
5083 Al Alloy

An ultrafine grained structure was obtained in the two grades of a 5083 Al alloy with or without scandium by using equal channel angular pressing and its superplastic behavior was characterized. For the alloy without scandium, low temperature superplasticity was obtained but high strain rate superplasticity was unlikely to occur. By contrast, the alloy containing a small amount of scandium exhibited high strain rate superplasticity. It was found that, in both cases, the strain rate region showing superplasticity was very limited, i.e. one order of magnitude. From the mechanical data, the deformation mechanisms were examined.

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