• Title/Summary/Keyword: Mg and Mg-Al alloy

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Effect of Flux on Recovery of Aluminum During Molten Metal Treatment of Aluminum Can Scrap (알루미늄 캔 스크랩의 용탕처리 시 알루미늄 합금 회수에 미치는 플럭스의 영향)

  • Han, Chulwoong;Ahn, Byung-Doo;Kim, Dae-Guen;Lee, Man Seung;Kim, Yong Hwan
    • Resources Recycling
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    • v.29 no.1
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    • pp.70-80
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    • 2020
  • This study investigates the effect of flux type and mixing ratio on efficiency in aluminum can scrap recycling using induction furnace. The removal of surface coating layer of aluminum can scrap was possible through heat treatment at about 500 ℃ for about 30 min. The temperature for the melting process was set to be slightly above the melting temperature of the aluminium can scrap. The molten metal treatment was performed with different types of flux and mixing ratio. As a result, The optimum efficiency of Al recovery ratio was revealed when the process was performed with at least 3 wt.% of the flux (Salt and MgCl2 mixture of ratio 70:30) at 750 ℃. The mechanical property of the recovered Al alloy showed that the tensile strength is about 249 MPa and elongation is about 14 %. This result was found to be similar to the mechanical property of the virgin Al 5083 alloy.

Corrosion of High Strength and High Ductility Al-Mg Develpment Aluminum Alloy (고강도, 고연성 Al-Mg계 알루미늄 개발 합금의 내식성 특성)

  • Choe, In-Gyu;Kim, Si-Myeong;Kim, Sang-Ho
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.05a
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    • pp.155-156
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    • 2015
  • 최근 자동차 및 항공기의 경량화 관련하여 알루미늄 합금의 필요성이 높아지고 있으나, 자동차재료에 쓰이는 알리미늄 합금의 경우 높은 이온화 경향 때문에 Fe, Cu, Pb 등과 접촉하면 쉽게 부식되는 단점이 있다. 본 연구에서는 기존의 Magsimal-59 샘플과 본 연구에서 개발한 고용질, 저용질 Duplex 알루미늄 합금과의 내식성을 분극 및 갈바닉을 통해 확인하고, 균질화처리를 통해 내식성을 개선한다.

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Microstructure-Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al-Si (A390) Alloy

  • Kim, Soo-Bae;Cho, Young-Hee;Jung, Jae-Gil;Yoon, Woon-Ha;Lee, Young-Kook;Lee, Jung-Moo
    • Metals and materials international
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    • v.24 no.6
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    • pp.1376-1385
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    • 2018
  • Ultrasonic melt treatment (UST) was applied to an A390 hypereutectic Al-Si alloy in a temperature range of $750-800^{\circ}C$ and its influence on the solidification structure and the consequent increase in strength was investigated. UST at such a high temperature, which is about $100^{\circ}C$ above the liquidus temperature, had little effect on the grain refinement but enhanced the homogeneity of the microstructure with the uniform distribution of constituent phases (e.g. primary Si, ${\alpha}-Al$ and intermetallics) significantly refined. With the microstructural homogeneity, quantitative analysis confirmed that UST was found to suppress the formation of Cu-bearing phases, i.e., $Q-Al_5Cu_2Mg_8Si_6$, $Al_2Cu$ phases that form in the final stage of solidification while notably increasing the average Cu contents in the matrix from 1.29 to 2.06 wt%. A tensile test exhibits an increase in the yield strength of the as-cast alloy from 185 to 208 MPa, which is mainly associated with the solute increment within the matrix. The important role of UST in the microstructure evolution during solidification is discussed and the mechanism covering the microstructure-strengthening interrelationship of the ultrasonically treated A390 alloy is proposed.

Microstructural Features of Al Alloy 7N01 Welded by $CO_2$ Laser - Microsturctural Features of Full Penetration Joints - ($CO_2$ 레이저 용접한 7N01 Al합금의 미세조직 특징(I) - 완전용입 용접부의 미세조직 -)

  • 윤재정;강정윤;김인배;김대업
    • Journal of Welding and Joining
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    • v.19 no.4
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    • pp.429-436
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    • 2001
  • The effect of welding condition on the microstructures of the weld metal in A7N01 welded by $CO_2$ laser was investigated. The number of ripples was increased with decreasing power and increasing welding speed. In the bead without ripple lines, the subgrain microstructures distribution from the fusion line toward the center of the bead were in the order of cellular, dendritic and equiaxed dendrite. However, in the bead with ripple lines, cellular and dendritic were formed between the fusion boundary and the ripple line. Inaddition, those structures were also observed between the ripple line. Equiaxed dendrites were formed only at the center line region. Cellular and dendritics formed near the ripple line were larger than those formed near the fusion boundary. The cooling rates estimated by the dendrite arm spacing were in the range of 200 to 1150oC/s. Cooling rate was increased with decreasing the power and increasing the welding speed. Mg and Zn segregated at the boundaries of cellulars and dendritics, Mg was segregated more than Zn. The segregation of Mg and Zn decreased with increasing cooling rate. Hardness of the weld metal was lower than that of the base metal in all welding conditions and increased as the cooling rate increased.

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Effect of Samarium Addition on Microstructure and Thermal Conductivity of Al-Si-Cu Aluminum Alloy (Sm 첨가에 따른 Al-Si-Cu 알루미늄 합금의 미세조직 및 열전도도 변화)

  • Choi, Jin-Ju;Kang, Yubin;Im, Byoungyong;Lee, Chan-Gi;Kim, Hangoo;Park, Kwang Hoon;Kim, Dae-Guen
    • Korean Journal of Materials Research
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    • v.30 no.1
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    • pp.31-37
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    • 2020
  • In this study, the effects of Sm addition (0, 0.05, 0.2, 0.5 wt%) on the microstructure, hardness, and electrical and thermal conductivity of Al-11Si-1.5Cu aluminum alloy were investigated. As a result of Sm addition, increment in the amount of α-Al and refinement of primary Si from 70 to 10 ㎛ were observed due to eutectic temperature depression. On the other hand, Sm was less effective at refining eutectic Si because of insufficient addition. The phase analysis results indicated that Sm-rich intermetallic phases such as Al-Fe-Mg-Si and Al-Si-Cu formed and led to decrements in the amount of primary Si and eutectic Si. These microstructure changes affected not only the hardness but also the electrical and thermal conductivity. When 0.5 wt% Sm was added to the alloy, hardness increased from 84.4 to 91.3 Hv, and electric conductivity increased from 15.14 to 16.97 MS/m. Thermal conductivity greatly increased from 133 to 157 W/m·K.

Microstructures and Mechanical Properties of AZ31-(0~0.5%)Ca alloys (AZ31-(0~0.5)%Ca 합금의 미세조직과 기계적 성질)

  • Jun, Joong-Hwan;Park, Bong-Koo;Kim, Jeong-Min;Kim, Ki-Tae;Jung, Woon-Jae
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.5
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    • pp.299-304
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    • 2004
  • Influence of Ca addition on microstructure and room temperature mechanical properties has been studied for AZ31(Mg-3%Al-1%Zn-0.2%Mn)-(0~0.5)%Ca wrought alloys, based on experimental results from metallography, X-ray diffractometry and mechanical tests. Yield strength, ultimate tensile strength and hardness of the alloys increased remarkably with increasing Ca content, whereas elongation was deteriorated continuously. Microstructural examination revealed that Ca addition efficiently refined grains of ${\alpha}$(Mg) phase and that some of the Ca dissolved in ${\beta}(Mg_{17}Al_{12})$ precipitates. The former and the latter facts are thought to be responsible for improved strength and loss of ductility of the AZ31+Ca wrought alloys, respectively.

The Composition of the Rare Earth Based Conversion Coating Formed on AZ91D Magnesium Alloy

  • Chang, Menglei;Wu, Jianfeng;Chen, Dongchu;Ye, Shulin
    • Corrosion Science and Technology
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    • v.17 no.1
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    • pp.1-5
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    • 2018
  • As structural materials, magnesium (Mg) alloys have been widely used in the fields of aviation, automobiles, optical instruments, and electronic products. There are few studies on the effect of coating conditions on the compositional variation during the formation process of the conversion coatings. Rare-earth based conversion coating on AZ91 magnesium alloy was prepared in ceric sulfate and hydrogen peroxide contained solution. The element composition and valence as well as their distribution in the coating were analyzed with energy dispersive X-ray spectroscopy (EDS), Electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS). The effect of treating process on the element composition were also studied. It was found that the conversion coating surface consists of Mg, Al, O, Ce, and the weight content of Ce in the coating was affected by the treating solution concentration and immersion time; the Ce element was distributed in the coating non-uniformly and existed in the form of $Ce^{+3}$ and $Ce^{+4}$, while the O element existed in the form of $OH^-$, $O^{2-}$, $H_2O$. Based on microscopic analysis results, the electrochemical deposition mechanism on the micro-anode and micro-cathode in the process of the coating growth was suggested.

Microstructure and Corrosion Properties of Plasma Electrolytic Oxide Coatings on AZ31 Magnesium Matrix Composite (플라즈마 전해 산화 처리한 AZ31 및 Al18B4O33w/AZ31 마그네슘 복합재료 피막의 미세구조 및 부식특성)

  • Cheon, Jinho;Park, Yongho;Park, Ikmin
    • Korean Journal of Metals and Materials
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    • v.49 no.3
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    • pp.270-274
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    • 2011
  • Plasma electrolytic oxidation (PEO) treatment was performed on squeeze cast AZ31 alloy and $Al_{18}B_4O_{33}w/AZ31$ composite. Scanning electron microscope (SEM) was employed to characterize the surface morphology and cross-section microstructure of the coating. The phase structures of the PEO coating were analyzed by X-ray diffraction (XRD). The corrosion resistance of the PEO coating was evaluated by electrochemical method. The results showed that the $Al_{18}B_4O_{33}$ whisker on the surface of the composite was decomposed and $MgAl_2O_4$ was formed in the PEO coating layer of $Al_{18}B_4O_{33}w/AZ31$ composite during PEO treatment. As a result, the electrochemical corrosion potential of the PEO coated $Al_{18}B_4O_{33}w/AZ31$ composite was increased compared with that of AZ31 alloy.

Effect of aging treatment on the microstructures and mechanical properties of 6N01 Aluminium alloy (6N01 Al 합금의 미세조직 및 기계적 성질에 미치는 시효처리의 영향)

  • Kang, Min-Cheol;Koo, Hung-Suh;Yun, In-Taeg;Kang, Chung-Yun;Kim, In-Bae
    • Journal of the Korean Society for Heat Treatment
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    • v.11 no.4
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    • pp.268-273
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    • 1998
  • Effect of aging treatment on the microstructures and mechanical properties of 6N01 Aluminium alloy was investigated by differential scanning calorimetry, transmission electron microscopy, microhardness measurement and tensile test. It was found that the precipitation sequence of 6N01 Aluminium alloy was GP zone ${\rightarrow}$ metastable hexagonal $Mg_2S_i({\beta}^{\prime})$,${\rightarrow}$ equilibrium fcc $Mg_2S_i({\beta})$, and the precipitates at peak aged condition were GP zones and ${\beta}^{\prime}$ phase. Microhardness changes during over aged condition showed very small decrease upon increased aging time. This result was attributed to the very slow transformation rate of ${\beta}^{\prime}$ to ${\beta}$. Maximum hardness(116 Hv) and tensile strength(312.6MPa) with 22.3% elongation were obtained from the specimen aged at $180^{\circ}C$ for 15hrs.

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Effect of Aging on the Interfacial Characteristics of ${Al_{18}}{B_4}{O_{33}}$/AS52 Mg Matrix Composite by Squeeze infiltration (용탕가압침투법으로 제조한 ${Al_{18}}{B_4}{O_{33}}$/AS52 Mg기 복합재료의 계면 특성에 미치는 시효의 영향)

  • Park, Yong-Ha;Park, Yong-Ho;Cho, Kyung-Mox;Park, Ik-Min
    • Journal of Korea Foundry Society
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    • v.28 no.6
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    • pp.268-272
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    • 2008
  • Interfacial characteristics of aluminum borate whisker reinforced AS52 matrix composite was investigated. Peak hardness of AS52 composite was obtained aging at $170^{\circ}C$ for 15h and the aging process was accelerated by the presence of the aluminium borate whisker. The MgO layer, which was the interfacial reaction product between the reinforcement and the Mg matrix, was produced with 20 nm thickness in as-cast condition. As the aging time increased, the thickness of the interfacial reaction layer increased to 50 nm in peak aged condition. The nano-indentation test results indicated that the strength of interface was improved by the aging but over-aging degraded the reinforcement and decreased the interfacial strength which resulted in the decrease of overall composite strength.