On the microstructural aspects of the nonhomogeneity of superplastic deformation at the level of grain groups

Zelin, M. G.; Krasil’nikov, N. A.; Valiev, Ruslan Z.; Grabski, M.W.; Hong, Yi; Mukherjee, Amiya K.

doi:10.1016/0956-7151(94)90054-x

Cited by 74 publications

(22 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…3) because of the size of grains initially evolved in the unrecrystallized regions is ∼ 3 times smaller than that of the recrystallized grains, and this size tends to approach to an equilibrium value (∼ 15 µm) for this temperature-strain rate conditions. 1,24) The grain aspect ratio, defined as the ratio of the grain dimension in the longitudinal direction to that in the transverse direction increases at ε ≤ 1.1 and remains essentially constant with further straining. Figure 5 represents typical orientation image microscopy (OIM) maps for superplastically deformed specimens; Fig.…”

Section: Microstructural Evolution 331 Optical Microscopymentioning

confidence: 99%

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

et al. 2002

View full text Add to dashboard Cite

The microstructure evolution in a 7055 aluminum alloy subjected to thermomechanical processing (TMP) was studied at 450 • C anḋ ε = 1.7 × 10 −3 s −1 at which the material exhibits superplastic behavior with a total elongation of 720% and the coefficient m = 0.58. Partially recrystallized initial structure of the as-processed 7055 Al consisted of bands of recrystallized grains with a mean size of 11 µm alternating with bands of recovered subgrains with a mean size of 2 µm. The true stress-true strain curve exhibits a well-defined peak stress, followed by gradual strain softening. The coefficient of strain rate sensitivity, m, remains unchanged at ε ≤ 1 and tends to decrease with strain at ε > 1. The initial microstructure persists near the peak strain. Following strain leads to evolution of initial partially recrystallized structure into uniform fully recrystallized structure due to occurrence of continuous dynamic reactions, i.e. continuous dynamic recrystallization (CDRX). The data of microstructural observation and misorientation analysis show that low-angle boundaries (LAB) gradually convert to high-angle boundaries (HAB) resulting in an extensive flow softening. It was shown that grain boundary sliding (GBS) provides superplastic flow at all strains. Concurrently, GBS plays an important role in the dynamic evolution of new grains facilitating conversion of LABs to HABs.

show abstract

Section: Microstructural Evolution 331 Optical Microscopymentioning

confidence: 99%

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

et al. 2002

View full text Add to dashboard Cite

show abstract

“…At all examined strain rates the grain groups slide as an entity (Astanin et al, 1994;Zelin and Mukerjee, 1995;Zelin et al, 1994). Evidence of CGBS was revealed at all studied deformation conditions.…”

Section: Surface Microstructural Observationsmentioning

confidence: 88%

“…The aim of this paper is to report experimental results concerning microstructural and texture changes of the composite PM 2014-20% A1203 during superplastic deformation and to discuss the operative deformation mechanism in the light of the concept of CGBS (Astanin et al, 1994;Zelin et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Texture and Microstructure Evolution During Superplasticity of theMetal Matrix Composite PM 2014 Al–20% Al₂O₃

Кайбышев

Kazyhanov

1999

Texture, Stress, and Microstructure

View full text Add to dashboard Cite

The effects of superplastic deformation (SPD) on grain structure and texture evolution of the A1 2014-20%A1203 composite produced via powder metallurgical method were investigated in conjunction with surface relief observations. Samples were deformed in tension at different strains in the range of true strain rates 10-4-10 -1 at temperature 500C. It was found that SPD strains have a large effect on both texture and grain size. At the initial stage of superplastic flow, deformation bands are formed in the aluminum matrix along the tension direction. Simultaneously, the initial (1 1) fiber texture is broken and formation of (1 10) fiber texture takes place. Further strain up to 50% leads to grain structure change from banded structure to nearly equiaxed. The (1 1) fiber texture is restored and texture intensity decreases with increasing strain. Strain rate dependence of texture developments showed evidence for dislocation activity in examined strain range. The relation between microstructure evolution and texture development during superplastic deformation of the PM 2014-20% A1203 composite is explained from the viewpoint of cooperative grain boundary sliding (CGBS).

show abstract

“…These large cavities developed by plasticitycontrolled cavity growth mechanism suggest that the cavitation is a result of extensive and non-uniform GBS. 18) This observation suggests a plasticity-controlled cavity growth mechanism, indicating cavitation is a result of extensive and non- uniform GBS. 13) Notably, even at 450…”

Section: Microstructural Evolutionmentioning

confidence: 93%

High Strain Rate Superplasticity in an Al-Li-Mg Alloy Subjected to Equal-Channel Angular Extrusion

et al. 2002

View full text Add to dashboard Cite

The superplastic behavior of an Al-4.1%Mg-2.0%Li-0.16%Sc-0.07%Zr alloy (1421 Al) subjected to intense plastic straining by equalchannel angular extrusion (ECAE) was studied in the temperature interval 250-450 • C at strain rates ranging from 1.4 × 10 −5 to 1.4 s −1 . The grain size after ECAE was about 0.8 µm and the fraction of high angle boundaries was about 80 pct. The highest elongation of 1850% without failure appeared at a temperature of 400 • C and initial strain rate of 1.4 × 10 −2 s −1 with corresponding coefficient of the strain rate sensitivity of 0.6. It was shown that the ECAE processed 1421 Al exhibits superior superplastic properties in the temperature range 300-450 • C with the strain rate sensitivity higher than 0.4. Microstructural evolution and cavitation during high strain rate superplastic deformation were examined.

show abstract

On the microstructural aspects of the nonhomogeneity of superplastic deformation at the level of grain groups

Cited by 74 publications

References 10 publications

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

Texture and Microstructure Evolution During Superplasticity of theMetal Matrix Composite PM 2014 Al–20% Al₂O₃

High Strain Rate Superplasticity in an Al-Li-Mg Alloy Subjected to Equal-Channel Angular Extrusion

Contact Info

Product

Resources

About

On the microstructural aspects of the nonhomogeneity of superplastic deformation at the level of grain groups

Cited by 74 publications

References 10 publications

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

Texture and Microstructure Evolution During Superplasticity of theMetal Matrix Composite PM 2014 Al–20% Al2O3

High Strain Rate Superplasticity in an Al-Li-Mg Alloy Subjected to Equal-Channel Angular Extrusion

Contact Info

Product

Resources

About

Texture and Microstructure Evolution During Superplasticity of theMetal Matrix Composite PM 2014 Al–20% Al₂O₃