• 열처리공학회지
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• 제33권3호
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• pp.117-123
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• 2020

Due to high corrosion resistance, Zinc has been widely used in the automobile, shipping or construction industries as a galvanizing material. Zinc is popular as a coating element, but its low mechanical strength impede the expansion of applications as a load-bearing structure. The mechanical strength of Zinc can be increased through zinc based alloy process, but the ductility is significantly reduced. In this study, the mechanical strength and ductility of Zinc-Magnesium alloys with respect to heat treatment hold time was investigated. In order to enhance the mechanical strength of Zinc, a Zinc-Magnesium alloy was fabricated by a melting process. The heat treatment process was performed to improve the ductility of Zinc-Magnesium alloy. The microstructure of the heat-treated alloy specimen was analyzed using SEM. The hardness and compressive strength of the specimen were measured by a micro-hardness tester and a nano-indenter, respectively.

• 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.

• 한국안전학회지
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• 제31권2호
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• pp.83-89
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• 2016

As the world's industrial development quickens, the highways and regional expressways have been expanding to serve the logistics and transportation needs of people. The burgeoning road construction has led to a growing interest in roadside installations. These must have reliable performance over long periods, reduced maintenance and high durability. Steel roadside barriers are prone to corrosion and other compromises to their functionality. Therefore, using high anti-corrosion steel material is now seen as a viable solution to this problem. Thus, the objective of this paper is to expand the scope of applications for high anti-corrosion steel material for roadside barriers. This paper assesses the impact safety such as structural performance, occupant protection performance and post-impact vehicular response performance by a simulation review on roadside barriers built with high strength anti-corrosion steel materials named as hot-dip zinc-aluminium-magnesium alloy-coated steel. The simulation test results for the roadside barriers built with high strength anti-corrosion steels with reduced sectional thickness meet the safety evaluation criteria, hence the proposed roadside barrier made by high strength and high anti-corrosion hot-dip zinc-aluminium-magnesium alloy-coated steel will be a good solution to serve safe impact performance as well as save maintenance cost.

• 한국산학기술학회논문지
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• 제17권3호
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• pp.171-176
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• 2016

본 논문은 도로안전시설물의 공용중 부식 발생으로 인한 기능 손실을 줄일 수 있는 방안으로 고내식성 용융합금도금 강판을 적용한 도로안전시설물을 제안한다. 고내식성 용융합금도금강판을 적용한 도로안전시설물 제품에 대한 신뢰성 있는 충돌성능 평가 기초자료를 제공할 목적으로 고내식강이 적용된 교량난간 제품에 대한 충돌 시뮬레이션 및 실물 차량 충돌시험 연구를 수행한다. 시뮬레이션 및 실차충돌 시험 결과, 변형률 속도 의존성을 고려할 수 있는 정교한 동특성 재료모델을 도입한 충돌 시뮬레이션을 통해 얻어지는 충돌 거동과 실물 차량 충돌 시험 결과가 매우 유사한 것으로 도출되었다. 본 논문에서 제안된 고내식성 용융합금도금 강판을 적용한 교량난간은 실물 차량 충돌 시험의 충돌성능 평가 기준을 모두 충족시켜 현장 적용을 앞두고 있다.

• 소성∙가공
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• 제33권1호
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• pp.12-17
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• 2024

Aluminum-zinc-magnesium alloy is a well-known alloy that is both strong and lightweight. Precipitation strengthening plays a significant role in the strength mechanism of this alloy, with nano-sized η-based precipitates being the representative precipitates. However, the growth of η precipitates can lead to a decrease in strength, necessitating research into ways to control their growth. In this study, we observed the atomic-level behavior of η₂ precipitates and discovered that the precipitates grew through a combination with magnesium after a zinc segregation layer was formed around them.

• 한국주조공학회지
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• 제31권4호
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• pp.212-217
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• 2011

The effects of alloying element and grain refinement on the tensile properties of magnesium alloy poured into sand mold were investigated. The strength of magnesium alloy was greatly increased by the addition of aluminium and that was increased with the increased aluminum content added up to 8.10 wt% and decreased beyond that. Even though the strength of Mg-8.10 wt%Al alloy was rather decreased by the addition of zinc, that was increased with increased zinc content added up to 0.50 wt% and decreased with the increased one beyond that. The maximum tensile strength was obtained with 0.50 wt%Mn added. The strength and elongation were simultaneously increased with grain refinement and the optimum amount of strontium addition for this was 0.30 wt%. The optimum chemical composition was obtained and the yield strength, tensile strength and elongation of the alloy with this composition were 90.2, 176.3MPa and 4.43%, respectively.

• 한국표면공학회지
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• 제44권6호
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• pp.239-245
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• 2011

Magnesium alloys is the lightest by structural metals, but it is not good corrosion resistant because of pit, void. Particularly, AZ31B magnesium alloy sheets that have slag, scratch by rolling process indicate some defects. The objective of this research is to perform uniform plating on AZ31B by studying etching and zincate process. Especially, zincate treatment by zinc salt and pyrophosphate is the most important in the decoration plating. Dissolution of magnesium is reduced by the formation of uniform zinc conversion layer during strick and post process, which decreases defects for plating process.

• Corrosion Science and Technology
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• 제2권2호
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• pp.102-108
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• 2003

The surface treatments. Chrome/Manganese and Modified Chrome Pickle, that are treated to improve the anti-corrosion property which is needed to increased the probability of prototype product enabled the sand cast Magnesium test specimens to have better corrosion resistance than non-treated one. Sand cast Magnesium specimens which was treated only with chemical conversion coating had same corrosion resistance with the Steel specimens plated by Zinc, and the another one that had the finishing treatment(painting) worked on the chemical surface treatment had the corrosion resistance property to meet to FPO-3 requirement. We also investigated the multiple finishing system(chemical surface treatment + 3 coating) to test the severe condition that magnesium should to endure.

• 한국표면공학회지
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• 제46권3호
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• pp.116-119
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• 2013

To improve the corrosion resistance of an electrogalvanized steel sheet, we deposited magnesium film on it using a vacuum evaporation method and annealed the films at $250-330^{\circ}C$. The zinc-magnesium alloy is consequently formed by diffusion of magnesium into the zinc coating. From the anodic polarization test in 3% NaCl solution, the films annealed at $270-310^{\circ}C$ showed better corrosion resistance than others. In X-ray diffraction analysis, $ZnMg_2$ was detected through out the temperature range, whereas $Mg_2Zn_{11}$ and $FeZn_{13}$ were detected only in the film annealed at $310^{\circ}C$. The depth composition profile showed that the compositions of Mg at $270-290^{\circ}C$ are evenly and deeply distributed in the film surface layer. These results demonstrate that $270-290^{\circ}C$ is a proper temperature range to produce a layer of $MgZn_2$ intermetallic compound to act as a homogeneous passive layer.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.62-62
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• 2013

Magnesium alloys exhibit many attractive properties such as low density, high strength/weight ratio, high thermal conductivity, very good electromagnetic features and good recyclability. However, most commercial magnesium alloys require protective coatings because of their poor corrosion resistance. Attempts have been made to improve the corrosion resistance of the Mg alloys by surface treatments, such as chemical conversion coatings, anodizing, plating and metal coatings. Among them, chemical conversion coatings are regarded as one of the most effective and cheapest ways to prevent corrosion of Mg alloys. In this study, the effects of various $Zn^{2+}$ concentrations and pH levels on the formation of zinc phosphate conversion coatings (ZPCCs) on AZ31 magnesium alloy were investigated, and corrosion resistances of the coated samples were evaluated by immersion test and potentiodynamic polarization experiment. The corrosion resistance of the coated AZ31 samples was found to increase with increasing $Zn^{2+}$ concentration and the lowest corrosion rate was obtained for the samples coated at pH of 3.07, independent of $Zn^{2+}$ concentration. The best coatings on AZ31 were obtained at [$Zn^{2+}$] = 0.068 M and pH 3.07. At the conditions of [$Zn^{2+}$] = 0.068 M and pH 3.07, the formation and growth processes of ZPCCs on AZ31 Mg alloy are divided into four stages: formation of a dense layer, precipitation of fine crystals on the dense layer, growths of the inner and outer layers, and reorganization of outer crystalline layer.