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Papers by Kwang Suk Son
ISIJ International, 2012
Hot dip aluminizing (HDA) is an effective way to improve the high temperature corrosion resistanc... more Hot dip aluminizing (HDA) is an effective way to improve the high temperature corrosion resistance and scaling resistance of ferrous materials. The formation of intermetallic compound layers between the two materials is a dominant factor in determining the properties of hot dip aluminized steel. The formation behavior of the intermetallic compound layer between a Si alloyed Al melt and cast iron has been investigated. The thickness of the intermetallic compound layer was significantly reduced as a result of the increased carbon content of the cast iron matrix. The thickness of the intermetallic compound layer formed in the Al-Si-Fe three-component alloy system remains constant in the early stage of the reaction, and it becomes increasingly rough with increased reaction time. The increased roughness could be attributed to the increased Fe concentration in the Al-Si melt near the cast iron surface, which is a result of the increased inter-diffusion of Al, Si and Fe atoms with increased reaction time by which the formation, melting and spallation of the intermetallic compound layer is enhanced.
Korean Journal of Metals and Materials, 2010
ABSTRACT The hot tear susceptibility of Al alloys was investigated by using a constrained-rod mol... more ABSTRACT The hot tear susceptibility of Al alloys was investigated by using a constrained-rod mold designed to quantify 8 types of tear tendency. The severity of the crack was scored by 5 grades on a scale of 0 to 4, with 0 being "no crack formed" and 4 being "complete separation by crack". The Hot Tear Susceptibility index (HTS) which consists of crack type scores and position scores, was proposed to compare the hot tear tendency of Al alloys. A356.0 cast alloy and AA6061 wrought Al alloy showed an HTS value of 27.5 and 53 respectively. The effects of Si, Cu, and Mg content on hot tear tendency were also investigated with a constrained-rod mold. The variation of HTS values with alloying elements represents similar behavior in the variation of the solidification range in a pseudo binary phase diagram.
Physica Status Solidi (c), 2003
Effects on structural characteristics of growth temperature and Si doping in GaN thin films grown... more Effects on structural characteristics of growth temperature and Si doping in GaN thin films grown on high temperature GaN were investigated. The GaN/GaN homojunction structure was grown via MOCVD at intermediate temperature (IT, 840 °C) with various Si doping concentrations. V-shaped pits are observed on the surface of the undoped GaN grown at IT by AFM morphology analysis. TEM two beam images show that only screw- and mixed-type components of dislocations contribute to pit formation. Moderate Si doping reduces the pit density, but over-doping of Si deteriorates the IT-GaN property by forming pits again. Not all pits are related with threading dislocations but some of them are observed in the dislocation free area of high Si-doped GaN. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
ISIJ International, 2012
Hot dip aluminizing (HDA) is an effective way to improve the high temperature corrosion resistanc... more Hot dip aluminizing (HDA) is an effective way to improve the high temperature corrosion resistance and scaling resistance of ferrous materials. The formation of intermetallic compound layers between the two materials is a dominant factor in determining the properties of hot dip aluminized steel. The formation behavior of the intermetallic compound layer between a Si alloyed Al melt and cast iron has been investigated. The thickness of the intermetallic compound layer was significantly reduced as a result of the increased carbon content of the cast iron matrix. The thickness of the intermetallic compound layer formed in the Al-Si-Fe three-component alloy system remains constant in the early stage of the reaction, and it becomes increasingly rough with increased reaction time. The increased roughness could be attributed to the increased Fe concentration in the Al-Si melt near the cast iron surface, which is a result of the increased inter-diffusion of Al, Si and Fe atoms with increased reaction time by which the formation, melting and spallation of the intermetallic compound layer is enhanced.
Korean Journal of Metals and Materials, 2010
ABSTRACT The hot tear susceptibility of Al alloys was investigated by using a constrained-rod mol... more ABSTRACT The hot tear susceptibility of Al alloys was investigated by using a constrained-rod mold designed to quantify 8 types of tear tendency. The severity of the crack was scored by 5 grades on a scale of 0 to 4, with 0 being "no crack formed" and 4 being "complete separation by crack". The Hot Tear Susceptibility index (HTS) which consists of crack type scores and position scores, was proposed to compare the hot tear tendency of Al alloys. A356.0 cast alloy and AA6061 wrought Al alloy showed an HTS value of 27.5 and 53 respectively. The effects of Si, Cu, and Mg content on hot tear tendency were also investigated with a constrained-rod mold. The variation of HTS values with alloying elements represents similar behavior in the variation of the solidification range in a pseudo binary phase diagram.
Physica Status Solidi (c), 2003
Effects on structural characteristics of growth temperature and Si doping in GaN thin films grown... more Effects on structural characteristics of growth temperature and Si doping in GaN thin films grown on high temperature GaN were investigated. The GaN/GaN homojunction structure was grown via MOCVD at intermediate temperature (IT, 840 °C) with various Si doping concentrations. V-shaped pits are observed on the surface of the undoped GaN grown at IT by AFM morphology analysis. TEM two beam images show that only screw- and mixed-type components of dislocations contribute to pit formation. Moderate Si doping reduces the pit density, but over-doping of Si deteriorates the IT-GaN property by forming pits again. Not all pits are related with threading dislocations but some of them are observed in the dislocation free area of high Si-doped GaN. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)