• Title/Summary/Keyword: Initial Texture

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Grain Growth and Texture Evolution of Mg: Phase Field Modeling (마그네슘의 결정립 성장과 집합조직: 상장모델 계산)

  • Kim, Dong-Uk;Cha, Pil-Ryung
    • Journal of Powder Materials
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    • v.18 no.2
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    • pp.168-171
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    • 2011
  • We investigate grain growth behavior of poly-crystalline Mg sheet having strong basal fiber texture using phase field model for grain growth and micro-elasticity. Strong initial basal texture was maintained when external load was not imposed, but was weaken when external biaxial strain was imposed. Elastic interaction between elastic anisotropy of Mg grain and external load is the reason why texture evolution occurs.

Damage Evolution and Texture Development During Plate Rolling (판재 압연에서의 결함성장과 집합조직의 발전)

  • 이용신
    • Transactions of Materials Processing
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    • v.9 no.4
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    • pp.372-378
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    • 2000
  • A process model including the effects of both the texture development and ductile damage evolution In plane strain rolling is presented. In this process model, anisotropy from deformation texture and deterioration of mechanical properties due to growth of micro voids are directly coupled Into the virtual work expressions for the momentum and mass balances. Special treatments in obtaining the initial values of field variables in the nonlinear simultaneous equations for the anisotropic, dilatant viscoplastic deformation are also given. Mutual effects of the texture development and damage evolution during plate rolling are carefully examined in terms of the distribution of strain components, accumulated damage, R-value as well as yield surfaces.

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Texture and Rolling Characteristics of AZ31 Magnesium Alloy (AZ31 마그네슘의 집합조직변화와 압연특성)

  • Akramov, S.;Kim, In-Soo
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.480-481
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    • 2008
  • The aim of this work is to compare the microstructure, the texture, of an AZ31 Mg alloy processed via cold rolling process. Initial AZ31 Mg alloy sheet samples with strong {0002} texture were cut along the angles of 12.5 and 25 degrees to normal direction (ND). These specimens were rolled in room temperature condition. The microstructure was characterized by optical microscopy and the texture was measured by X-ray diffraction.

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Effect of Initial Texture on the Evolution of Warm Rolling Texture and Microstructure in Aluminum Alloy Sheet (알루미늄 판재의 온간압연 집합조직과 미세조직에 미치는 초기 집합조직의 영향)

  • Kim H. D.;Huh M. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.10a
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    • pp.138-141
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    • 2001
  • The evolution of lectures and microstructure during the warm-rolling and subsequent annealing in aluminum 3004 alloy sheets was investigated by employing X-ray texture measurements and microstructure observations. Whereas the typical $\beta$-fiber orientations with the strong Bs-orientation $\{112\}<110>$ formed in the normally cold-rolled specimen, the warm-rolling at $250^{\circ}C$ led to the development of a strong through thickness texture gradient which was characterized by shear texture at the surface layer and rolling textures at the center layer After warm rolling, ultra-fine grains formed in the thickness layer with shear texture components. Upon recrystallization annealing, the $\{001\}<100>$ Cube-texture developed at the expense of normal rolling texture components the rise to the formation of corase recrystallized grains. However, in the layer with shear texture components the continuous recrystallization took place and the fine grain size persisted even after recrystallization annealing.

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Changes of Texture and Plastic Strain Ratio of Asymmetrically Rolled and Annealed Cu Sheet (I) (비대칭 압연과 열처리한 Cu 판의 집합조직과 소성변형비 변화 (I))

  • Lee, C.W.;Lee, D.N.;Kim, I.
    • Transactions of Materials Processing
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    • v.28 no.6
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    • pp.354-360
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    • 2019
  • The plastic strain ratio is one of the factors that affect the deep drawability of metal sheets. The plastic strain ratio of fully annealed Cu sheet is low because its texture has {001}<100>. In order to improve the deep drawability of Cu sheet, it is necessary to increase the plastic strain ratio of Cu sheet. This study investigate the increase of plastic strain ratio of a Cu sheet after the first asymmetry rolling and annealing, and the second asymmetry rolling and annealing in air and Ar gas conditions. The average plastic strain ratio (Rm) was 0.951 and |ΔR| value was 1.27 in the initial Cu sheet. After the second 30.1% asymmetric rolling and annealing of Cu sheet at 1000℃ in air condition, the average plastic strain ratio (Rm) was 1.03 times higher. However, |ΔR| was 0.12 times lower than that of the initial specimen. After the second 18.8% asymmetric rolling and annealing of Cu sheet at 630℃ in Ar gas condition, the average plastic strain ratio (Rm) was 1.68 times higher and |ΔR| was 0.82 times lower than that of the initial specimen. These results are attributed to the change of the texture of Cu sheet due to the different annealing conditions.

Texture and Plastic Strain Ratio Changes of Hot Asymmetrically Rolled AA3003 Sheet (열간 비대칭 압연한 AA3003 판재의 집합조직과 소성변형비 변화)

  • Hamrakulov, B.;Lee, C.W.;Kim, I.
    • Transactions of Materials Processing
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    • v.28 no.5
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    • pp.281-286
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    • 2019
  • The plastic strain ratio is one of the factors of the deep drawability of metal sheets. The plastic strain ratio of Al sheet is low value. Therefore, it is necessary to increase the plastic strain ratio in order to improve the deep draw ability of the Al sheet. This study investigated the increase of the plastic strain ratio and the texture change of AA3003 sheet after the hot asymmetric rolling. The average plastic strain ratio of the initial AA3003 sheets was 0.69. After 83% hot asymmetric rolling at $200^{\circ}C$, the average plastic strain ratio was 0.83. The average plastic strain ratio of the 83% hot asymmetrically rolled AA3003 sheet at $200^{\circ}C$ is 1.2 times higher than that of the initial AA3003 sheet. The ${\mid}{\Delta}R{\mid}$ of 83% hot asymmetrically rolled AA3003 sheet at $200^{\circ}C$ is 0.83 times lower than that of the initial AA3003 sheet. This result is due to the development of the intensity of ${\gamma}-fiber$ texture and reduces the intensity of {001}<110> and {001}<100> textures after hot asymmetric rolling of AA3003 sheet.

Fabrication of Ni substrates made by powder metallurgy and casting method (초기시편 제조법에 따른 Ni substrate의 특성비교)

  • 임준형;김규태;김정호;장석헌;주진호;나완수;지봉기;전병혁;김찬중
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.55-58
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    • 2003
  • We fabricated the textured Ni substrate and evaluated the effects of processing variables on microstructural evolution and texture transformation. Ni-rods as an initial specimen were prepared by two different methods, i.e., powder metallurgy(P/M) and plasma arc melting(PAM) The texture of the substrate was characterized by pole-figure and surface condition was evaluated by atomic force microscopy. It was observed that the texture of substrate made by P/M did not significantly varied with annealing temperature of 800~120$0^{\circ}C$ and the full-width at half-maximums (FWHM) of both in-plane and out-of-plane were 9$^{\circ}$~10$^{\circ}$. On the other hand, the texture of substrate made by PAM was more dependent on the annealing temperature and the FWHMs of in-plane texture was 9$^{\circ}$~13$^{\circ}$ at the temperature range. In addition, twin texture, (221)<221>, was formed as the temperature increased further. The grain size of substrate made by P/M was smaller than that made by PAM and this difference was correlated to the microstructure of initial specimens.

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Texture and Plastic Strain Ratio Changes with the Number of Passes of Asymmetric Rolling in AA1050 Al Alloy Sheet (비대칭 압연 패스 회수에 따른 AA1050 Al 판재의 집합조직과 소성변형비 변화)

  • Nam, Su-Kwon;Jeong, Hae-Bong;Kim, In-Soo
    • Transactions of Materials Processing
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    • v.19 no.8
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    • pp.502-507
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    • 2010
  • The physical and mechanical properties and formability of sheet metals depend on preferred crystallographic orientations (texture). In this research work, the texture development and formability (plastic strain ratios) of AA1050 Al alloy sheets after 3 and 10 passes of asymmetric rolling and subsequent heat treatment were investigated. The plastic strain ratios of 10 passes asymmetrically rolled and subsequent heat treated samples are 1.3 times higher than those of the initial AA1050 Al alloy sheets. The ${\Delta}r$ of 10 passes of asymmetrically rolled and subsequent heat treated samples is 1/30 times lower than those of the initial AA1050 Al alloy sheets. The plastic strain ratios of 10 passes of asymmetrically rolled and subsequent heat treated Al sheets are higher than those of 3 passes ones. These results could be attributed to the formation of $\gamma$-fiber, ND//<111>, and the other texture components by means of asymmetric rolling in Al sheets.

Deformation Behavior during Warm Rolling in AA3103 Sheet deformed by CCSS (CCSS 가공한 AA3103 판재에서 온간 압연 소성 거동)

  • Lee J. P.;Kang H. K.;Huh M. Y.;Park J. W.;Chung Y. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.215-217
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    • 2004
  • In order to obtain the initial starting sample having a random texture and fine grains, aluminum alloy 3103 sheets were repeatedly deformed by CCSS up to six passages and subsequently annealed at $300^{\circ}C$ for 1h. These samples were cold rolled at room temperature and also warm rolled at $250^{\circ}C$. Changes in rolling temperature gave rise to the different texture evolution. Warm rolling led to the pronounced texture gradients comprising the shear texture at the surface and the rolling texture at the sheet center. The formation of the rolling texture components, i.e., the ${\beta}$-fiber, was promoted by cold rolling than warm rolling.

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Effects of cp-Ti Surface Roughness and Directionality on Initial Cell Attachment Behaviors

  • Shin, Dong-Hoon;Chun, Sungsu;Ahn, Myun-Whan;Song, In-Hwan;Kim, Sukyoung
    • Korean Journal of Metals and Materials
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    • v.50 no.4
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    • pp.338-343
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    • 2012
  • The early osseointegration of titanium (Ti) dental implants is related to the initial cell morphology. The morphology of the cells (mesenchymal stem cells, MSC) was observed on three different Ti disc surfaces, which were mechanically treated by polishing, blasting, and scratching. A non-directional surface (isotropic texture) was obtained by the blasting of HA grits on cp-Ti discs, and a unidirectional surface (anisotropic texture) was obtained by the scratching of SiC papers. The cell attachment and arrangement in the initial periods were quite similar, but those in the later periods were significantly affected by the texture of the cp-Ti discs. After 1 week, the blasted Ti discs showed non-directional arrangement or spreading of the cells, whereas the scratched cp-Ti discs showed unidirectional properties parallel to the direction of the scratched grooves on the surface. The surface roughness of the cp-Ti discs significantly affects cell proliferation. Cell proliferation on the blasted and scratched surfaces was about 60% and 40% higher compared to the control result (polishing group) after 1 week (P<0.05). Cell proliferation on the blasted and scratched surfaces after 1 week was slightly enhanced with increasing surface roughness. It is believed that the direction of cell attachment and arrangement is closely related to the surface texture of the substrate surfaces, but cell proliferation after a relatively long period of time is directly enhanced by the surface roughness, not by the surface texture.