Texture Segregation and Texture Change in the Biaxial Stretching of AA6016

2005 ◽  
Vol 495-497 ◽  
pp. 585-590 ◽  
Author(s):  
Pete S. Bate ◽  
M. Moore ◽  
S.A. Court
Keyword(s):  
Grain Size ◽  
Finite Element Modelling ◽  
Texture Evolution ◽  
Sheet Thickness ◽  
Texture Segregation ◽  
Element Modelling ◽  
Biaxial Stretching ◽  
Texture Change ◽  
Initial Texture ◽  
Significant Factors

Sheets of the Al-Mg-Si alloy AA6016 have been prepared with different microstructures by rolling and annealing, followed by heat treatment to the T4 condition. These have been biaxially stretched using the Marciniak driving blank method, and their limit strains measured. Such biaxial stretching limits are very sensitive to inhomogeneity with length scales greater than about half the sheet thickness, and significant factors in that inhomogeneity are the materials grain size and the spatial segregation of texture. In this material, it appears that colonies of cube textured grains have an effect on the limit strains. However, there is significant change of texture during stretching and this texture evolution also needs to be considered. Finite element modelling has been used to evaluate the effects of grain size, clustering of the initial texture and texture evolution on the biaxial stretching limits.

scholarly journals Predicting the Effects of Grain Size on Machining-Induced Residual Stresses in Steels

2014 ◽  
Vol 996 ◽  
pp. 634-639 ◽  
Author(s):  
Mohamed N.A. Nasr
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Residual Stresses ◽  
Finite Element Modelling ◽  
Material Strength ◽  
Grain Size Effect ◽  
Inverse Relation ◽  
Lower Yield ◽  
Element Modelling ◽  
Lower Yield Strength

The current study examines the effect of grain size on machining-induced residual stresses (RS), during turning, using finite element modelling. Based on the well-known inverse relation between grain size and material strength, the grain size effect was simulated via changing the workpiece yield strength. This was also done at different strain hardening rates. The model was validated using four materials. Larger grain size (lower yield strength) resulted in higher surface tensile RS. This is attributed to the surface layer being subjected to higher compressive plastic deformation, as well as higher workpiece temperatures, which both contribute to higher tensile RS.

Application of Multiscale Crystal Plasticity Models to Forming Limit Diagrams

2004 ◽  
Vol 126 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Robert D. McGinty ◽  
David L. McDowell
Keyword(s):  
Texture Evolution ◽  
Sheet Thickness ◽  
Rate Sensitivity ◽  
Measured Data ◽  
Forming Limit ◽  
Initial Thickness ◽  
Forming Limit Diagrams ◽  
Polycrystal Plasticity ◽  
Parametric Studies ◽  
Initial Texture

A polycrystal plasticity model is used to conduct parametric studies of forming limit diagrams (FLD) and to compare with experimental data. The Marcinak and Kuczynski [13] method is applied. It is confirmed that the onset of necking is retarded by increases in the ratio of initial band to sheet thickness and material strain rate sensitivity. It was also demonstrated that initial texture plays an important role in FLD response, as has been shown in other recent studies [6,26,7]. It is shown that a texture resulting from plane strain compression to one-tenth of the initial thickness gives a predicted FLD that more closely matches measured data than that based on an initially isotropic texture. The influence of a relatively softer response in terms of effective stress in torsional shear than in compression (i.e., shear softening) on FLDs is investigated with the aid of a hardening surface formulation along with the polycrystal plasticity texture evolution model. It is shown that necking behavior can be significantly affected by shear softening, particularly for initially textured sheets. It is also demonstrated that the hardening surface formulation provides additional flexibility in modeling FLD behavior beyond that afforded by classical polycrystal plasticity.

On the Thickness Effect of Axisymmetric Deformation of Sheet Metals

1984 ◽  
Vol 106 (2) ◽  
pp. 208-209
Author(s):  
Shyam K. Samanta ◽  
G. Grab
Keyword(s):  
Finite Element ◽  
Theoretical Analysis ◽  
Finite Element Modelling ◽  
Sheet Thickness ◽  
Fold Increase ◽  
Axisymmetric Deformation ◽  
Thickness Effect ◽  
Forming Limit ◽  
Sheet Metals ◽  
Element Modelling

In the present investigation, we have studied the influence of sheet thickness on the limiting strain, i.e., forming limit, of a mild steel by punch stretching experiments. Our results show that for a two-fold increase in thickness the limiting strain of a material does not substantially increase with increasing thickness of the sheet. These experimental observations were well supported by the results of theoretical analysis using Finite Element modelling of the process.

Role of deformation twin on texture evolution in cold-rolled commercial-purity Ti

2008 ◽  
Vol 23 (11) ◽  
pp. 2954-2966 ◽  
Author(s):  
Yong Zhong ◽  
Fuxing Yin ◽  
Kotobu Nagai
Keyword(s):  
Grain Size ◽  
Cold Rolling ◽  
Texture Evolution ◽  
Dislocation Slip ◽  
Commercial Purity ◽  
High Deformation ◽  
Prediction And Control ◽  
Initial Texture ◽  
Deformation Level ◽  
Cp Ti

Texture evolution of a commercial-purity titanium (CP-Ti) during cold rolling was studied by means of x-ray diffraction (XRD) and electron back-scattered diffraction (EBSD). Twinning was identified to significantly contribute to deformation up to reductions of about 50%. Based on initial texture of the material investigated and twinning modes available in hexagonal close-packed (HCP) structures, the measured texture evolution can be interpreted in terms of (i) compressive twinning ({11¯22}〈11¯2¯3〉) within the two dominant initial texture components B ({0001}〈10¯10〉±40°TD) and E ({0001}〈11¯20〉±40°TD) and (ii) followed by tensile twinning ({10¯12}〈10¯1¯1〉) in the then-favorably reoriented twinned part. Reduction of grain size at high deformation inhibits further twinning and results in a stable texture evolution driven exclusively by dislocation slip. During cold rolling, the crystals of the initial texture component B first rotate to orientation M ({01¯10}〈2¯1¯12〉) by compressive twinning (primary), and then orientation M rotates to orientation D ({0001}〈11¯20〉) by tensile twinning (secondary). Meanwhile, the crystals of the initial component E first rotate to the orientation M′ ({14¯53}〈6¯5¯13〉) by compressive twinning (primary), and then orientation M′ rotates to the orientation A ({0001}〈10¯10〉) by tensile twinning (secondary). At higher deformation level, twinning was significantly depressed by strongly refined grain size, which resulted in the elimination of the transient texture components caused by slip. These results are useful for the prediction and control of the texture in titanium.

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