• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.128-131
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• 2004

Magnesium alloys are being extensively used in weight-saving applications and as a potential replacement for plastics in electronic and computer applications. Magnesium alloy has some good characteristics, EMI shielding property and high specific strength. Nevertheless their high brittleness make it uneasy to process the magnesium. Magnesium alloys are extruded like aluminium alloys. The present work was done to find a characteristic of magnesium alloy(AZ31) changing the extrusion ratio 8.5, 19.1, 49 respectly and changing the die half angle $30^{\circ},\;45^{\circ},\;60^{\circ}$. Here this present done by the hydrostatic extrusion in the hot condition, $310^{\circ}$. The higher the extrusion ratio goes, the higher the extrusion force goes.

• 대한금속재료학회지
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• 제48권3호
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• pp.241-247
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• 2010

In order to develop the vacuum distillation process of magnesium alloy scrap, a fundamental study on the evaporation behavior of magnesium alloy (AM50) scrap melt was carried out. Melt temperature, pressure, reaction time, and initial specific surface area of melt were considered as experimental variables. The evaporation rate of magnesium increased with the increase of melt temperature and initial specific surface area of melt, and with the decrease of the pressure. The activation energy of magnesium evaporation reaction calculated by an Arrhenius plot decreased with the decrease of the pressure and with the increase of the initial specific surface area of melt. An empirical equation was derived for the evaporation rate of magnesium from AM50 alloy melt.

• 한국기계가공학회지
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• 제8권2호
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• pp.69-75
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• 2009

This study is analyzed by impact simulation according to material property at terminal case of hand phone. Maximum equivalent stress or strain at plastic is 40 times as great as that at magnesium alloy. And the next greatest stress or strain is shown at aluminium alloy. The value of maximum equivalent stress is shown as 6.5 Mpa in case of plastic, magnesium alloy and aluminium alloy. Maximum shear strain at plastic is 40 times as great as that at magnesium alloy. And the next greatest strain is shown at aluminium alloy. The value of deformation or strain at magnesium alloy and aluminium alloy is not different.

• 한국자동차공학회논문집
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• 제19권1호
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• pp.139-146
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• 2011

In present study, it aims to compare the noise and vibration characteristics between magnesium alloy and steel hood panel. The AZ31 magnesium hood panel was fabricated through warm forming process, and the noise and vibration characteristics between both hood panels was compared through the measurement of engine radiation noise and transmission loss, as well as FRF on modal analysis. The sound insulation performance of magnesium alloy was wholly superior to that of steel hood panel, even though the transmission loss of magnesium alloy is lower than that of steel due to mass effect primarily. The FRF characteristics on modal analysis indicates that the resonance frequency of magnesium hood panel is remarkably increased to higher value than that of steel hood panel. The radiation and interior noise of magnesium panel even without acoustic hood insulation were remarkably lower than those of steel hood panel with acoustic insulation, in particular, at a range below 4,000 rpm.

• 대한금속재료학회지
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• 제50권9호
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• pp.619-627
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• 2012

One of the barriers limiting wide applications of magnesium alloys to various industries is their poor corrosion resistance. The corrosion properties of AZ91 magnesium alloy, which is the most popular magnesium casting alloy, are affected by microstructural and environmental factors. The corrosion properties of AZ91 magnesium alloy are affected by the corrosion properties of ${\alpha}-Mg$ and ${\beta}$ phases, the volume fraction and distribution of ${\beta}$ phase and area ratio of ${\alpha}-Mg/{\beta}$ phases. The corrosion properties of AZ91 magnesium alloy under various environments also change according to the passivity of films and types of corrosion products formed on its surface. The corrosion resistance of the magnesium alloys can be improved by microstructural control through the addition of alloying elements and optimization of the production process.

• 대한금속재료학회지
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• 제46권1호
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• pp.13-19
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• 2008

To develop a recycling process of magnesium alloy scrap, a fundamental study on the distillation of magnesium alloy melt was carried out. Melt temperature, vacuum degree and reaction time were considered as experimental variables. The amount of vaporized magnesium melt per unit surface area of melt increases with the increase of melt temperature, reaction time and vacuum degree. The vapor condensed at the tip of water cooling Cu-condenser as a form of pine cone. Magnesium and zinc were vaporized easily from the melt. However, It's difficult to separate magnesium and zinc by vacuum distillation because vapor pressure of zinc is similar to one of magnesium. The contents of aluminum, manganese and iron, etc. in residual melt increase due to the decrease of magnesium and zinc content after the distillation of magnesium alloy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.306-309
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• 2007

Recently, magnesium alloys have been widely used in automotive, aerospace and electronic industries with the advantages such as lightweightness, high specific strength and stiffness. However, magnesium alloy has quite low formability at room temperature due to its hexagonal close-packed crystal structure. Warm deep drawing is one of the forming technologies to improve the formability of magnesium alloy sheet and the lubrication condition is an important process parameter in that. In this study, the drawing tests of AZ31 alloy sheet at elevated temperature for various kinds of lubricant were carried out and the effects of lubrication conditions on drawbility were investigated.

• 한국융합학회논문지
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• 제12권5호
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• pp.17-22
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• 2021

환경 친화적인 마그네슘-공기 전지는 이론적 방전용량이 매우 높은 1차전지로 알려진 금속-공기 전지이며 대기 중 산소를 양극 활물질로 사용하고 마그네슘 합금을 연료로 사용하는 관점에서 금속-연료전지로도 불리고 있다. 음극으로 사용하는 마그네슘합금의 성능에 따라 전지 전체 성능이 결정되므로 고성능 전지로 상용화하기 위해서는 음극 재료인 마그네슘 합금 전극의 성능에 대한 연구와 개선이 필요하다. 본 연구는 상용화된 마그네슘 합금(AZ31, AZ61)을 선택하여 마그네슘-공기 전지용 전극재료로서 가능성을 평가하기 위하여 전기화학적인 측정을 실시하고 방전 특성을 조사하였다. 개방회로전위 변화, Tafel 곡선 변화, 순환전류전압곡선 측정을 통해 마그네슘합금들의 전기화학적 특성을 조사하였고 정전류 방전 실험을 통해 AZ61 합금의 우수한 방전 용량(1410mAhg^-1)과 가능성을 평가하였다.

• Corrosion Science and Technology
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• 제16권3호
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• pp.151-159
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• 2017

The MA8 alloy (formula Mg-Mn-Се) has been shown to have greater corrosion stability than the VMD10 magnesium alloy (formula Mg-Zn-Zr-Y) in chloride-containing solutions by Scanning Vibrating Electrode Technique (SVET) and by optical microscopy, gravimetry, and volumetry. It has been established that the crucial factor for the corrosion activity of these samples is the occurrence of microgalvanic coupling at the sample surface. The peculiarities of the kinetics and mechanism of the corrosion in the local heterogeneous regions of the magnesium alloy surface were investigated by localized electrochemical techniques. The stages of the corrosion process in artificial defects in the coating obtained by plasma electrolytic oxidation (PEO) at the surface of the MA8 magnesium alloy were also studied. The analysis of the experimental data enabled us to determine that the corrosion process in the defect zone develops predominantly at the magnesium/coating interface. Based on the measurements of the corrosion rate of the samples with PEO and composite polymer-containing coatings, the best anticorrosion properties were displayed by the composite polymer-containing coatings.

• 소성∙가공
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• 제15권6호
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• pp.453-458
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• 2006

While the die casting has been mainly used to manufacture the magnesium alloy parts, the press forming is considered as an alternative to the die casting for saving the manufacturing cost and improving the structural strength of the magnesium alloy parts. Because the magnesium alloy has low formability at room temperature, forming at elevated temperatures is a necessary condition to obtain the required material flow for press forming. However, the elevated temperature forming does not always guarantee the sufficient formability under the dry friction condition because the surface damage such as scratch or wear may accelerate the material failure. In the present study, the solid-type lubricants such as PTFE, graphite and $MoS_2$ were tested for the square cup warm deep drawing using the magnesium alloy AZ31 sheet. The formability improvement by using the lubricant was examined by comparing the maximum deep drawing depth using the PTFE against no lubricant. The formability difference for the different lubricant was also examined based on the maximum deep drawing depth.