• Transactions of Materials Processing
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• v.27 no.6
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• pp.379-385
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• 2018

This study investigated the effect of extrusion conditions on microstructures and mechanical properties of AM80 magnesium alloys. The billets of magnesium alloy used for hot extrusion were prepared by permanent mold casting method, and its extrusion was hot direct extrusion with different extrusion conditions. The results of microstructural analysis showed that the main phases in the as-casted alloys were ${\alpha}-Mg$, ${\beta}-Mg_{17}Al_{12}$, and lamella $Mg_{17}Al_{12}$. Hot extrusion results, The tensile strength of the most soundly manufactured extruded bars (extrusion temp: $350^{\circ}C$, extrusion ratio: 27:1, ram speed: 2mm/s) was approximately 327MPa at room temperature. The increase in the mechanical properties of hot-extruded alloys was as a result of grain refinement by dynamical recrystallization during hot extrusion.

• Journal of Korea Foundry Society
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• v.26 no.1
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• pp.34-39
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• 2006

In the present study, the possibility of Mg-Zn-Y alloys as high temperature casting alloys has been investigated. The fluidity of alloys containing yttrium were better than that of commercial AZ91 alloy because the oxide layer on the surface reduced the reaction between melt, and air and mold, which would reduce the resistance during the process of filling the mold. However, this oxide film reduced the hot-tearing resistance. In the case of ZAW942, this alloy exhibited fluidity and hot-tearing resistance better than AZ91 alloy. Because of thermally stable quasicrystal and other phases obstructed the movement of grains, the creep resistance of alloys containing rare earth elements more than 2 wt% was better than that of AZ91 alloy.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.68-68
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• 1994

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.80-80
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• 1997

• Journal of Korea Foundry Society
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• v.35 no.2
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• pp.36-43
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• 2015

In this study, the influences of aluminum and tin additions (individual and combined) on corrosion behavior of magnesium alloy have been determined. The studied alloys were fabricated by permanent mold casting method to measure the corrosion properties, a potentiodynamic test, hydrogen evolution test and immersion test were carried out in a 3.5% NaCl solution at pH 7.2. From the results of microstructure analysis, the Mg-9Al-1Zn alloy was found to be composed of ${\alpha}$-Mg and rod-like $Mg_{17}Al_{12}$ phase and the Mg-5Sn-5Al-1Zn alloy was found to be composed of ${\alpha}$-Mg, rod-like $Mg_{17}Al_{12}$ and $Mg_2Sn$ phases. In the case of the Mg-9Sn-1Zn alloy, the microstructure was composed of ${\alpha}$-Mg and eutectic $Mg_2Sn$ phase. With Sn addition (individual and combined), the corrosion resistance of the Mg alloys improved.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.2
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• pp.9-17
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• 2018

Aluminum (Al) and its alloys have been used widely in a variety of industries such as structural, electronic, aerospace, and particularly automotive industries due to their lightweight characteristic, outstanding ductility, formability, high oxidation and corrosion resistance, and high thermal and electrical conductivity. Al have different kinds of alloys according to the various additional elements system and they should be selected properly depending on their effectiveness and suitability for their particular purpose. The major elements for Al alloys are silicon (Si), magnesium (Mg), manganese (Mn), copper (Cu), and zinc (Zn). In order for Al alloys to use for each industry, it is necessary to study of Al to Al joining and/or the Al to dissimilar materials joining to combine the individual parts into one. Many studies on joining technologies about Al to Al and Al to dissimilar materials have been performed such as press joining, bolted joint, welding, soldering, riveting, adhesive bonding, and brazing. This study reviews a variety of Al alloys and their joining method including its principles and properties with recent trends.

• Journal of Korea Foundry Society
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• v.24 no.3
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• pp.165-174
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• 2004

The pore formation characteristic of Mg alloy during Lost Foam Casting(LFC) was investigated with reduced pressure test and real casting, which was compared with the results of previous work for Al alloy. Cast Mg alloys in LFC had much lower porosities in comparison with those of Al alloys. Also, the proper pouring temperature gave the minimum porosity like Al alloy although it was higher than that of Al alloys due to the worse fluidity of Mg alloy. The pore formation mechanism of Mg alloy in LFC was similar to that of AI alloy but the critical temperature showing the different mechanism is higher than that of Al alloy as much as $30{\sim}50^{\circ}C$. The result that Mg alloy in LFC had the lower porosity comparing with Al alloy was due to the extra solubility of hydrogen gas although the solubility of Al alloy was easily exceeded by the external sources like pyrolyzed polystyrene products. The mold evacuation gave the lower porosity due to the removal of polystyrene pyrolysis products, and reduced shrinkage defects. Also, there was a proper evacuation pressure that gave a porosity of almost 0vol%. But much higher vacuum degree than this proper pressure caused the severe entrapment of polymer pyrolysis products that gave the large porosity.

• Analytical Science and Technology
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• v.7 no.4
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• pp.517-526
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• 1994

Large insoluble phases and dispersoids in Al-Li-Cu-Mg-Mn-Zr alloys containing Mn were analyzed with EPMA(Electron Probe Microanalyzer) and SAEM(Scanning Auger Electron Microscope). Morphology, distribution and volume fraction of the large insoluble phase were also analyzed quantitatively by optical microscopy. Mechanical properties were tested at room temperature and at $200^{\circ}C$. With increasing Mn contents, the volume fraction of the large insoluble phases increased steeply, thus decreasing ductility. Mn was found to be very effective for obtaing uniformly distributed fine-grain structures. The alloy containing 0.44 wt% Mn showed the highest tensile strength among Mn-bearing alloys tested.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.1
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• pp.23-28
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• 2004

In this work, the effect of Sc and Mm(misch metal) on the high temperature behavior of Al-Mg alloys was observed. Hardness was increased due to appearance of fine $Al_3Sc$ precipitates. The elongation of Al-Mg-Sc alloy at high temperature was higher than that of Al-Mg-Sc-Mm alloy because Al-Mg-Sc alloy has finer grain sizes than Al-Mg-Sc-Mm alloy. The strain rate sensitivity factor, "m" of Al-Mg-Sc and Al-Mg-Sc-Mm at $475^{\circ}C$ and $1{\times}10^{-2}s^{-1}$ were 0.33 and 0.46, respectively. The activation energy of Al-Mg-Sc and Al-Mg-Sc-Mm alloy for superplastic deformation was 133KJ/mol and 103KJ/mol respectively. The elongation of Al-Mg-Sc alloy at high temperature was decreased by the addition of Mm, but the strength at high temperatures and low strain rate was improved.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.94-95
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• 2014

The purpose of this study is to evaluate the corrosion protective property of Al-Mg high-freqeuncy arc metal spray method in comparison to Zn-Sn and Zn-Al alloys by electrochemical method and CASS test. As a result, it appeared that Al-Mg alloy had very higher corrosion protective property through the electrochemical characteristic and the CASS test comparing with the other alloys.