Yield surface prediction of Aluminum on rolling

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[[image:rolling_texture_pcys.jpg|thumb|450px|right|Figure 1. Rolling simulation of polycrystal Aluminum. (a)Initial texture; (b) rolled texture; (c)yield surfaces at various rolling strain levels.]]
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== Abstract ==
 
== Abstract ==
  

Revision as of 12:17, 20 June 2011

Figure 1. Rolling simulation of polycrystal Aluminum. (a)Initial texture; (b) rolled texture; (c)yield surfaces at various rolling strain levels.

Contents

Abstract

Rolling of polycrystalline aggregates of Aluminum was investigated by employing the Visco-plastic self-consistent polycrystal (VPSC) model. The starting texture is a series crystals represented by five hundred random orientations. Rolled texture and yield surfaces at rolling strain levels of -0.5, -1.0, -1.5, -2.0 and -2.5 were captured by VPSC modeling. The predicted texture showed a typical rolled texture components and the yield surfaces showed anisotropic shape and a saturation tendency.

Author(s): Q. Ma, E.B. Marin, M.F. Horstemeyer


Methodology

Aluminum conducts rolling through only {111}<011> slips at room temperature. A starting texture represented by 500 random orientations was shown in Figure 1a. Single crystal parameters were listed in FCC.SX file as follow. The self-hardening and latent hardening were set equal to one in this example. The rolling boundary conditions were set as: restricted 2 direction (transverse direction), 1 direction (rolling direction) was free and 3 direction (normal direction) conducted rolling strain. The final rolled texture is displayed in Figure 1b. The yield surfaces at each strain levels were captured by VPSC modeling as shown in Figure 1c.



Input Data

The input data (fcc.sx) for Aluminum rolling simulation as follows:



*Material: Aluminum
cubic           crysym
   1.0   1.0   1.0   90.   90.   90.   unit cell axes and angles
Elastic stiffness (single crystal [MPa]; scaled=0.85xINTERPOLATED)
 108.2   61.3   61.3   000.0   000.0   000.0
 61.3   108.2   61.3   000.0   000.0   000.0
 61.3   61.3   108.2   000.0   000.0   000.0
 000.0   000.0   000.0   28.5   000.0   000.0
 000.0   000.0   000.0   000.0   28.5   000.0
 000.0   000.0   000.0   000.0   000.0   28.5
*Thermal expansion coefficients (single crystal in crystal axis):
 10.0e-6  10.0e-6  10.0e-6   0.0e0   0.0e0   0.0e0                    "alfacc"
*Info about slip & twinning modes in this file:
  2          nmodesx    (total # of modes listed in file)
  1          nmodes     (# of modes to be used in the calculation)
  1          mode(i)    (label of the modes to be used)
  <111>{110} SLIP
 1  12  20   1                           modex,nsmx,nrsx,iopsysx
 0.000   0       0.000   0.000           twshx,isectw,thres1,thres2
 3.7     30.0     20.0     0.0     0.  0.  tau0,tau1,thet0,thet1 ,hpfac,gndfac
       1.0   1.0                         hlat(nmodes)
   1  1  1        0  1 -1
   1  1  1        1  0 -1
   1  1  1        1 -1  0
  -1  1  1        0  1 -1
  -1  1  1        1  0  1
  -1  1  1        1  1  0
  -1 -1  1        0  1  1
  -1 -1  1        1  0  1
  -1 -1  1        1 -1  0
   1 -1  1        0  1  1
   1 -1  1        1  0 -1
   1 -1  1        1  1  0
  <111>{112} TWIN
 2  12  20   0                           modex,nsmx,nrsx,iopsysx
 0.707   0       0.100   0.500           twshx,isectw,thres1,thres2
 1.0     0.0     0.0     0.0     0.  0.  tau0,tau1,thet0,thet1 ,hpfac,gndfac
       1.0   1.0                         hlat(nmodes)
   1  1  1       -2  1  1
   1  1  1        1 -2  1
   1  1  1        1  1 -2
  -1  1  1        2  1  1
  -1  1  1       -1 -2  1
  -1  1  1       -1  1 -2
  -1 -1  1        2 -1  1
  -1 -1  1       -1  2  1
  -1 -1  1       -1 -1 -2
   1 -1  1       -2 -1  1
   1 -1  1        1  2  1
   1 -1  1        1 -1 -2



Results

Rolling process of polycrystal Aluminum was simulated by VPSC model. The typical rolled texture components and the yield surfaces at various strain levels can by captured by the VPSC model. VPSC can also capture both the crystal scale parameters (single crystal hardening parameters) and macroscale property (yield surfaces, stress-strain responses) of the polycrystalline aggregrate.

Acknowledgments

The authors are grateful to the financial support from the Department of Energy, Contract No. DE-FC-26-06NT42755, and the Center for Advanced Vehicular Systems (CAVS) at Mississippi State University.

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