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Simulation of Texture Evolution during Hot Rolling Deformation in FCC Materials
Choi, Shi Hoon,Song, Y.S.,Kim, B.J.,Kim, Hyoung Wook,Kang, Suk Bong Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.345-346 No.-
<P>The evolution of hot rolling texture in FCC materials has been simulated numerically using a visco-plastic self-consistent (VPSC) polycrystal model. A finite element (FE) analysis with ABAQUS/StandardTM was conducted to evaluate the deformation gradients during hot rolling deformation. In order to capture crystallographic rotation during hot rolling deformation, an octahedral slip system was considered in a microscopic hardening model. The FE analysis with the VPSC polycrystal simulations successfully predicted the inhomogeneous texture development through the thickness direction in the hot-rolled Al-5wt%Mg alloy sheets.</P>
Choi, Shi Hoon,Song, Y.S.,Kim, Jong Kweon,Jung, B.J.,Park, Yong Bum Trans Tech Publications, Ltd. 2007 Materials science forum Vol.558 No.-
<P>Uniaxial compression tests on hot-rolled AZ31 Mg alloy were carried out at a temperature of 300°C. In order to investigate work hardening and texture evolution during plastic deformation, cylindrical specimens were compressed to the rolling direction. Experimental investigation reveals that flow curves are strongly dependent on microstructure evolution such as deformation twinning and softening phenomenon. The occurrence of deformation twinning and softening phenomenon was revealed by the observation of microtexture using electron backscatter diffraction (EBSD). A visco-plastic self-consistent (VPSC) polycrystal model was used to simulate the work hardening, softening and texture evolution during the uniaxial compression. In order to calculate orientation of deformation twins, predominant twin reorientation (PTR) scheme was implemented into the polycrystal model. A softening scheme was also implemented in the polycrystal model to predict softening phenomenon and texture evolution after a peak stress.</P>
Texture Evolution during Hot Rolling Deformation in Al-5wt%Mg Alloy
Choi, Shi Hoon,Song, Y.S.,Kim, Jong Kweon,Kim, Hyoung Wook,Kang, Suk Bong Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.345-346 No.-
<P>Evolution of crystallographic texture by hot rolling deformation at the temperature of 200°C was investigated by hot rolling tests on as-cast Al-5wt%Mg alloy fabricated by a new strip cast technology. Texture variation through the thickness direction in the Al-5wt%Mg alloy was examined experimentally. Macrotexture and microtexture measurements were conducted using X-ray diffractometer and electron backscatter diffraction (EBSD), respectively. Experimental investigation reveals that the evolution of texture and microstructure is strongly dependent on a distance from center of the Al-5wt%Mg alloy sheet. It was found that the shear texture components tend to be increased at the surface region of the hot-rolled specimen.</P>
Shi-Hoon Choi,Dae-Wan Kim,Hoe-SeokYang,Seong-Ho Han,JeongWhan Yoon 한국소성가공학회 2010 기타자료 Vol.2010 No.6
Planar anisotropy and cup-drawing behavior were investigated for high-strength steel sheets containing different volume fractions of martensite. Macrotexture analysis using XRD was conducted to capture the effect of crystallographic orientation on the planar anisotropy of high-strength steel sheets. A phenomenological yield function, Yld96, which accounts for the anisotropy of yield stress and r-values, was implemented into ABAQUS using the user subroutine UMAT. Cup drawing of high-strength steel sheets was simulated using the FEM code. The profiles of earing and thickness strain were compared with the experimentally measured results.
최시훈 ( Shi Hoon Choi ),김형욱 ( Hyoung Wook Kim ),조재형 ( Jae Hyung Cho ),강석봉 ( Seok Bong Kang ),최재권 ( Jae Kwon Choi ) 대한금속재료학회 ( 구 대한금속학회 ) 2010 대한금속·재료학회지 Vol.48 No.7
Conventional rolling (symmetric) and differential speed rolling (DSR) were both applied to AA1050 sheets at various velocity ratios, from 1 to 2 between the top and bottom rolls. An electron backscatter diffraction (EBSD) technique was used to measure texture inhomogeneity through the thickness direction. After the annealing process, the annealing texture of the DSR processed sheets was different from that of conventionally rolled sheets. The velocity ratio between the top and bottom rolls affected the texture inhomogeneity and macroscopic plastic strain ratio of the AA1050 sheets. A prediction for the macroscopic plastic strain ratio of AA1050 sheets was carried out using a visco-plastic self-consistent (VPSC) polycrystal model. The strain ratio directionality that was predicted using the VPSC polycrystal model was in good agreement with experimental results.