• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.48-54
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• 2003

Alumium alloys casting are gaining increased acceptance in the automotive and electronic industeries and squeeze casting is the most efficient method of manufacturing such mass produced parts. This study has been investigated the microstructures and mechanical properties of Al-7.0Si-0.4Mg (AC4C) alloy fabricated by squeeze casting process for development of Fuel system Parts (Fuel rail). The microstructure of squeeze casted specimen were composed of eutectic structure Alumimim solid solution and $Mg_2$Si precipitates. The tensile strength of as-solid solution treatment Al-7.0Si-0.4Mg ahoy revealed 298.5MPa. It was found that Al-7.0Si-0.4Mg alloy have good corrosion resistance in electrochemical polarization test.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3398-3405
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• 2021

This study observed the effect of neutron irradiation and ageing on the microstructure, hardness, and corrosion resistance of SAV-1 (Al-Mg-Si) alloy. The investigated material was irradiated with neutrons to fluences of 10²¹-10²⁶ n/m² in the WWR-K research reactor and kept in dry storage. Long-term irradiation led to an increase in hardness of the alloy and a deterioration of pitting corrosion resistance. Post-irradiation ageing for 1 h at 100-300 ℃ resulted in a decrease in microhardness of the irradiated SAV-1. The effect of post-irradiation ageing on pitting corrosion was made clear through the formation of Guinier-Preston zones and secondary precipitates in the Al matrix. Ageing at 250 ℃ corresponded to the development of stable microstructure and the highest corrosion resistance for the irradiated samples. Mg₂Si, Si, and needle-shaped β" precipitates were formed in SAV-1 alloy that was irradiated with low fluences. β" and clusters of rod-shaped B-type precipitates were observed in highly irradiated samples. The precipitates were similar to those seen in non-irradiated pseudo-binary Al-Mg₂Si alloys with Si excess.

• Journal of the Korean institute of surface engineering
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• v.48 no.5
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• pp.227-232
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• 2015

Corrosion characteristic of the duplex Al-Mg-Si alloys with low, commercial and high solute contents were studied using an anodic polarization test in 1M NaCl solution at room temperature. Polarization range condition of the experiment were form .0.3V to .1.3V with a 0.2 mV scanning speed. The exchange current density means corrosion rate of the low solute alloy was low as about $16.29{\mu}A/cm^2$, and that of the high solute alloy was high as $84.92{\mu}A/cm^2$. The difference was mainly attributed to the inter-granular precipitates $Mg_2Si$ and Si which could make a galvanic corrosion on the aluminum base. The amount of precipitates was greater in high solute alloy at mainly in grain boundary. While, the extruded alloys had better corrosion resistance than the cast alloy because the silicon precipitates become coarse during the extrusion process.

• Journal of Power System Engineering
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• v.7 no.4
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• pp.44-48
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• 2003

Alumium alloys casting are gaining increased acceptance in the automotive and electronic industeries and squeeze casting is the most efficient method of manufacturing such mass produced parts. This study has been investigated the microstructures and mechanical properties of Al-7.0Si-0.4Mg(AC4C)alloy fabricated by squeeze casting process for development of Engine Mountain Bracket. The microstructure of squeeze casted specimen were composed of eutectic structure Alumimim solid solution and $Mg_2Si$ precipitates. The tensile strength of as-solid solution treatment Al-7.0Si-0.4Mg alloy revealed 2985MPa. It was found that Al-7.0Si-0.4Mg alloy have good aging hardening effect results are presented to show the validity of the control method.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.66-71
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• 2008

Alumium alloys hot forging process are gaining increased acceptance in the automotive and electronic industries and hot forging is one of the most efficient manufacturing method for mass product parts. It has been investigated the microstructures and mechanical properties of Al-11.7Si-0.5Mg (KNT40-T6)alloy fabricated by hot forging process for development of connecting rod in this study. The microstructure of hot forged specimen was composed of eutectic structure of alumimum solid solution and $Mg_2Si$ precipitates. The tensile strength of solutionized Al-11.7Si-0.5Mg alloy was 217MPa. This alloy showed a good corrosion resistance using electrochemical polarization test.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1301-1306
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• 2006

Aluminum alloys are gaining increased acceptance in the automotive and electronic industeries and cold & hot forging is the most efficient method of manufacturing such mass produced parts. This study has been investigated the microstructures and mechanical properties of A6061(Al-1.2Mg-0.8Si) alloy fabricated by cold & hot forging process for development of the future compressor block. The microstructure of cold & hot forginged specimen were composed of eutectic structure aluminum solid solution and $Mg_2Si$ precipitates. The tensile strength of as-solid solution treatment A6061 alloy revealed 291.7MPa. It was fabricated that a trial future compressor cylinder block using cold & hot forging.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.5
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• pp.561-569
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• 2008

We analyzed contents of cations and anions for the domestic bottled drinking water. Results showed that total cation content was 45.81 mg/L and contained 40% of Ca. The content of cations were decreased in the order of Ca>Si>Na>Mg>K. Total anion content was 12.20 mg/L and contained 90% of ${SO_4}^{2-}$ and $Cl^-$. $F^-$ and $NO_{3-}N$ were a little contained. While Si content was reduced 2.3~75.7%(mean value:38.5%) after freezing, Ca content was reduced 45.2% after boiling. It showed that water containing higher Ca content was significantly decreased after boiling. Precipitates formed by freezing and boiling is composed of minerals such as Si and Ca. Compared to minerals from food intake, concentrations of minerals from water intake are expected to be less influenced. It is recommended Bottled Water that contains more than 20 mg/L of Ca(exceeding water-quality standard for turbidity) is safe to drink without thawing and boiling.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.56-59
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• 2005

Aluminum alloy casting is gaining increased acceptance in automotive and electronic industries and especially, squeeze casting is the most efficient method of mass manufacturing of such parts. In this study, the microstructures and mechanical properties of Al-7.0Si-0.4Mg(AC4C) alloy fabricated by squeeze casting process for development of fuel system parts (fuel rail) are investigated. The microstructure of squeeze cast specimen was composed of eutectic structure aluminum solid solution and $Mg_2Si$ precipitates. The tensile strength of as-solid solution treatment Al-7.0Si-0.4Mg alloy was 298.5MPa. It was found that Al-7.0Si-0.4Mg alloy had good corrosion resistance in electrochemical polarization test.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.3
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• pp.144-148
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• 2011

Change in damping capacity with strain amplitude was studied in Mg-Al-Si alloy in as-cast, solution-treated and aged states, respectively. The as-cast microstructure of the alloy is characterized by eutectic ${\beta}$($Mg_{17}Al_{12}$) phase and Chinese script type $Mg_2Si$ particles. The solution treatment dissolved the ${\beta}$ phase into the matrix, while the aging treatment resulted in the distribution of continuous and discontinuous type ${\beta}$ precipitates. The solution-treated microstructure showed better damping capacity than as-cast and aged microstructures both in strain-dependent and strain-independent damping regions. The decrease in second-phase particles which weakens the strong pinning points on dislocations and distribution of solute atoms in the matrix, would be responsible for the enhanced damping capacity after solution treatment.

• Journal of the Mineralogical Society of Korea
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• v.27 no.3
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• pp.125-134
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• 2014

The Janggun mine (Longitude $E129^{\circ}$ 03' 40", Latitude $N36^{\circ}$ 51' 19") was once operated as an underground mine and recently significant amount of mine and leachate water has been discharged from the mine adits and tailing dumps. Mine and leachate waters are characterized by neutral to weakly basic pH values (6.81-9.59). Major cations and anions have concentrations between 6.70-129.80 mg/L of Mg, 289.29-661.02 mg/L of Ca, 4.74-14.38 mg/L of Mn and 1205.00-2448.69 mg/L of $SO{_4}^{2-}$. Brownish yellow precipitates that found in the stream bottom consist of poorly crystallized 2-line ferrihydrite ($Fe_2O_3{\cdot}0.5H_2O$. Scanning electron microscope (SEM) photographs show that brownish yellow precipitates consisted of micro-sized granular particles of about $0.1{\mu}m$ in diameter. Semi-quantitative energy dispersive spectrometry (EDS) analyses show that these samples contained mainly Fe with minor Mn, Ca, Si and As.