Papers by Author: No Jin Park

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Authors: Jong Tae Park, Hyung Don Joo, Dae Hyun Song, Kyung Jun Ko, No Jin Park
Abstract: Desirable magnetic properties for grain oriented electrical steels are low core loss and high magnetic flux density. These properties are closely related with sharpness of {110} texture. This Goss texture develops by abnormal grain growth during secondary recrystallization annealing. Based on experimental results, a general suggestion which estimates the magnetic properties after completion of secondary recrystallization from a primary recrystallized texture can be proposed. For a material to have better magnetic properties after completion of secondary recrystallization, it should have a primary recrystallized texture in which there are not only large number of ideal Goss grains, but also lower frequency of low angle grain boundary around those Goss grains.
726
Authors: Chang Wan Ha, Sung Ji Choi, No Jin Park
Abstract: In this study, the magnesium alloys AZ31, ZK10, and ZEK100 are investigated through microstructure, texture, and tensile test. The sheets were hot rolled, and different results were found for different chemical compositions. The contained elements affected the grain size, shear band, twins, and intensity of the basal texture of the magnesium alloy. Thus, if a magnesium sheet had finer grains and a weak (00.1) texture because of its chemical composition, it had the most favorable formability.
382
Authors: Sang Hoon Lee, No Jin Park, David P. Field, Paul R. Besser
Abstract: For optimum fabrication and usage of Cu films, an understanding of the relationship between processing and microstructure is required. The existence of twins is another significant factor for texture development in Cu films. Texture character and strength in the Cu film is dependent on the twin boundary development that is a function of processing conditions and film thickness. In this study, determination of grain growth and texture in the sputtered and electroplated Cu films during annealing was performed for films of 100, 480 and 850 nm in thickness deposited on a Ta(25 nm)/Si wafer. The texture was measured by X-ray pole figure. The effect of film thickness on the annealing texture in the sputtered and electroplated Cu films is examined and discussed.
982
Authors: No Jin Park, Chang Wan Ha
Abstract: Mg alloys are drawing a lot of attention and have been extensively studied. The major obstacle to the practical application of the alloys is the poor formability at room temperature, originating basically from the insufficient number of slip system. Development of a proper microstructure and/or texture is one promising solution to improve the formability. In the present work, after extrusion and full annealing, rolling at 300°C with different starting textures, the microstructures, texture developments and tensile properties of AZ31 Mg alloys are studied. After full annealing strong ∥ED fiber texture and weak + ∥ED fiber texture (c-axes in the radial direction) were developed. After rolling at 300°C many twins were formed, and the strong ∥ED fiber texture changed to ∥ND texture. Yield strength, tensile strength and elongation changed obviously depending on the microstructure and textures.
354
Authors: No Jin Park, Sun Hea Hwang
Abstract: Magnesium alloys have attracted a great deal of attention and have been extensively studied, but there is still a major obstacle to their practical application, namely, their poor formability at room temperature, which basically originates from their insufficient number of slip systems. The development of a microstructure and/or texture that is more conducive to formability is one promising solution that could improve their formability. In the present work, the microstructures, textures, and tensile properties of AZ31 Mg alloys are studied following extrusion and full annealing and rolling at 100 and 300°C. After full annealing, a strong ∥ED fiber texture and a weak + ∥ED fiber texture (c-axes in the radial direction) were developed. After 40% rolling at 100°C, many deformed twins were observed and a relatively weak texture was developed. The basal poles were split and rotated about 20° to the rolling direction (RD). During 60% rolling at 300°C, dynamic recrystallization (DRX) took place and a strong ∥ND fiber texture was developed, and this had an influence on the alloys’ poor formability at room temperature.
76
Authors: No Jin Park, S.J. Jin, C.W. Jea, Seong Taek Lim, Yong Yun Lee, Dong-Seok Chung
Abstract: After extrusion, cold rolling and T-6 treatment, microstructure, texture development, and deep drawability of Al-5.09%Zn-1.83%Mg-0.32%Cu-0.25%Mn-alloy with 0.1% Sc are studied. After T-6 treatment, recrystallized equiaxed grains with an average grain size of 1~2㎛ are obtained. During extrusion the very strong <111>-fiber + medium sharp <100>-fiber + weak <210>-fiber texture is developed, which influences the formation of rolling texture. The texture, after 80% cold rolling, can be described by the strong {112}<111>(Cu) + {123}<634>(S) component in the cross section of the extruded rod, the strong b-fiber + weak {110}<001>(Goss) components in the longitudinal section, and the strong {110}<112>(Bs) + weak {001}<100>(Cube) components in the transverse section. The types of rolling texture are not changed after the T-6 treatment, but the maximum density of ODF is higher. The calculated mean r-values, rm, and the planar anisotropy, Dr, are relatively high, which are dependent on the texture.
213
Authors: Seng Ho Yu, Dong Hyuk Shin, No Jin Park, Moo Young Huh, Sun Keun Hwang
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