• Title/Summary/Keyword: Casting Al alloy

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Effect of Alloying Elements on the Thermal Conductivity and Casting Characteristics of Aluminum Alloys in High Pressure Die Casting (고압 다이캐스팅용 알루미늄 합금의 열전도성 및 주조성에 미치는 첨가원소의 영향)

  • Kim, Cheol-Woo;Kim, Young-Chan;Kim, Jung-Han;Cho, Jae-Ik;Oh, Min-Suk
    • Korean Journal of Metals and Materials
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    • v.56 no.11
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    • pp.805-812
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    • 2018
  • High pressure die casting is one of the precision casting methods. It is highly productivity and suitable for manufacturing components with complex shapes and accurate dimensions. Recently, there has been increasing demand for efficient heat dissipation components, to control the heat generated by devices, which directly affects the efficiency and life of the product. Die cast aluminum alloys with high thermal conductivity are especially needed for this application. In this study, the influence of elements added to the die cast aluminum alloy on its thermal conductivity was evaluated. The results showed that Mn remarkably deteriorated the thermal conductivity of the aluminum alloy. When Cu content was increased, the tensile strength of cast aluminum alloy increased, showing 1 wt% of Cu ensured the minimum mechanical properties of the cast aluminum. As Si content increased, the flow length of the alloy proportionally increased. The flow length of aluminum alloy containing 2 wt% Si was about 85% of that of the ALDC12 alloy. A heat dissipation component was successfully fabricated using an optimized composition of Al-1 wt%Cu-0.6 wt%Fe-2 wt%Si die casting alloy without surface cracks, which were turned out as intergranular cracking originated from the solidification contraction of the alloy with Si composition lower than 2 wt%.

Effect of Cooling Rate on the Prediction of Mechanical Properties of Al Alloys (알루미늄 합금 주물의 냉각 속도에 따른 기계적 성질 예측)

  • Dong, Quan-Zhi;Cho, In-Sung;Hwang, Ho-Young
    • Journal of Korea Foundry Society
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    • v.32 no.5
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    • pp.225-230
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    • 2012
  • In this study, a more practical and simulation approach which can predict the mechanical properties of aluminum alloys is proposed. First, cooling rate, micro-structure, and mechanical properties of casting product were measured through casting experiment. The relation between cooling rate and SDAS decrease exponentially and the linearly decreasing relation exist between SDAS and mechanical properties. Then, the cooling rate was calculated by casting process simulation and the mechanical properties were predicted by using the relations that were derived through experiment. Experimentally measured mechanical properties and predicted values by simulation were in the range of relatively small difference. The mechanical properties of various Al alloys are expected to be predicted by the casting process simulation before actual casting.

Microstructure, Tensile Strength, and High Cycle Fatigue Properties of Mg+Al2Ca added ADC12 (Al-Si-Cu) Alloy (Mg+Al2Ca 첨가 ADC12 (Al-Si-Cu) 합금의 미세조직, 인장 및 고주기 피로 특성)

  • Kim, Y.K.;Kim, M.J.;Kim, Shae K.;Yoon, Y.O.;Lee, K.A.
    • Transactions of Materials Processing
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    • v.26 no.5
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    • pp.306-313
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    • 2017
  • This study investigated the microstructure, tensile strength, and high cycle fatigue properties of ADC12 aluminum alloys with different $Mg+Al_2Ca$ contents manufactured using die casting process. Microstructural observation identified the presence of ${\alpha}-Al$, eutectic Si, $Al_2Cu$, and Fe-intermetallic phases. The increase of $Mg+Al_2Ca$ content resulted in finer pore size and decreased pore distribution. Room temperature tensile strength tests were conducted at strain rate of $1{\times}10^{-3}/sec$. For 0.6%Mg ADC12, measured UTS, YS, and El were 305.2MPa, 157.0MPa, and 2.7%, respectively. For 0.8%Mg ADC12, measured UTS, YS, and El were 311.2 MPa, 159.4 MPa, and 2.4%, respectively. Therefore, 0.8% ADC12 alloy had higher strength and slightly decreased elongation compared to 0.6% Mg ADC12. High cycle fatigue tests revealed that 0.6% Mg ADC12 alloy had a fatigue limit of 150 MPa while 0.8% Mg ADC12 had a fatigue limit of 160MPa. It was confirmed that $Mg+Al_2Ca$ added ADC12 alloy achieved finer, spherical eutectic Si particles, and $Al_2Cu$ phases with greater mechanical and fatigue properties since size and distribution of pores and shrinkage cavities decreased as $Mg+Al_2Ca$ content increased.

Anodic Polarization Characteristics in Ti-20%Zr(-5%Cr) Alloys for Dental Castings (치과주조용 Ti-20%Zr(-5%Cr)합금의 양극분극특성)

  • Jung, Jong-Hyun;Han, Sok-Yoon
    • Journal of Technologic Dentistry
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    • v.26 no.1
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    • pp.41-48
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    • 2004
  • Ti-20%Zr(-5%Cr) alloys not containing harmful Al and V were newly designed in order to reveal their possibility for dental casting and melted in an arc melting and casting furnace under Ar atmosphere. The corrosion resistance was studied by anodic polarization test. From the observation of anodic polarization behavior, it was found that the corrosion resistance was markedly increased by the addition of Cr. The corrosion resistance of Ti-20%Zr-5%Cr alloy was superior to that in Ti-6%Al-4%V alloy but almost similar to that in CP Ti using in market place today.

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Elemental alteration of the surface of dental casting alloys induced by electro discharge machining (치과용 주조 합금의 방전가공에 따른 표면 성분 변화)

  • Jang, Yong-Chul;Lee, Myung-Kon
    • Journal of Technologic Dentistry
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    • v.31 no.1
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    • pp.55-61
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    • 2009
  • Passive fitting of meso-structure and super-structures is a predominant requirement for the longevity and clinical success of osseointegrated dental implants. However, precision and passive fitting has been unpredictable with conventional methods of casting as well as for corrective techniques. Alternative to conventional techniques, electro discharge machining(EDM) is an advanced method introduced to dental technology to improve the passive fitting of implant prosthesis. In this technique material is removed by melting and vaporization in electric sparks. Regarding the efficacy of EDM, the application of this technique induces severe surface morphological and elemental alterations due to the high temperatures developed during machining, which vary between $10,000{\sim}20,000^{\circ}C$. The aim of this study was to investigate the morphological and elemental alterations induced by EDM process of casting dental gold alloy and non-precious alloy used for the production of implant-supported prosthesis. A conventional clinical dental casting alloys were used for experimental specimens patterns, which were divided in three groups, high fineness gold alloy(Au 75%, HG group), low fineness gold alloy(Au 55%, LG group) and nonprecious metal alloy(Ni-Cr, NP group). The UCLA type plastic abutment patterns were invested with conventional investment material and were cast in a centrifugal casting machine. Castings were sandblasted with $50{\mu}m\;Al_2O_3$. One casting specimen of each group was polished by conventional finishing(HGCON, LGCON, NPCON) and one specimen of each group was subjected to EDM in a system using Cu electrodes, kerosene as dielectric fluid in 10 min for gold alloy and 20 min for Ni-Cr alloy(HGEDM. LGEDM, NOEDM). The surface morphology of all specimens was studied under an energy dispersive X-ray spectrometer (EDS). The quantitative results from EDS analysis are presented on the HGEDM and LGEDM specimens a significant increase in C and Cu concentrations was found after EDM finishing. The different result was documented for C on the NPEDM with a significant uptake of O after EDM finishing, whereas Al, Si showed a significant decrease in their concentrations. EDS analysis showed a serious uptake of C and Cu after the EDM procedure in the alloys studied. The C uptake after the EDM process is a common finding and it is attributed to the decomposition of the dielectric fluid in the plasma column, probably due to the development of extremely high temperatures. The Cu uptake is readily explained from the decomposition of Cu electrodes, something which is also a common finding after the EDM procedure. However, all the aforementioned mechanisms require further research. The clinical implication of these findings is related with the biological and corrosion resistance of surfaces prepared by the EDM process.

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A Study on the Fabrication of Semi-solid Al Alloys by EMS Horizontal Continuous Casting Process (전자교반식 수평연속주조법에 의한 반응고 Al 합금의 제조에 관한 연구)

  • Park, Gi-Beom;Song, Yeong-Bae;Kim, Yeong-Hwan;Kim, Gyeong-Heon;Kim, In-Bae
    • Korean Journal of Materials Research
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    • v.10 no.2
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    • pp.117-123
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    • 2000
  • In this study, to fabricate the semi-solid Al alloy, the 3phase-2poles electromagnetic stirring system was adopted. The changes of primary grain size, aspect ratio, standard deviation, hardness and the size morphology of eutectic Si with pouring temperatures and input voltages were investigated. At the same pouring temperature, with increasing input voltage, aspect ratio, standard deviation and primary grain size were decreased. The optimum condition for fabrication of semisolid Al alloys by EMS horizontal continuous casting process was determined that the input voltage was 220V and the pouring temperature was 68$0^{\circ}C$. At this optimum conditions the primary grain size was 54$\mu\textrm{m}$, the aspect ratio was 1.56 and the size of eutectic Si was 0.5$\mu\textrm{m}$. The micro-hardness of the Al alloy was 72.1 Hv. The semi-solid A356 Al alloy which has very low aspect ratio and standard deviation value could be fabricated by adopting the EMS horizontal continuous casting facility that was manufactured for this study.

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Permanent Mold Casting of Ti-6.0wt%Al-4.0wt%V Alloy Melt (Ti-6.0wt%Al-4.0wt%V 합금 용탕의 금형 주조)

  • Kang, Jang-Won;Kim, Myung-Yong;Lee, Sang-Kil;Lee, Hae-Jung;Kim, Kyung-Hoon;Lee, Hyo-Soo;Lim, Sung-Chul;Kwon, Huck-Chon
    • Journal of Korea Foundry Society
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    • v.27 no.3
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    • pp.135-139
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    • 2007
  • To produce higher quality of titanium casting at a lower cost, the new titanium casting technology by using a permanent metal mold was developed and applied to fabricate hip joint for biomedical application. The present study was carried out to investigate the reactivity and fluidity of the Ti-6.0 wt%Al-4.0 wt%V alloy with metal mold by applying various ceramic powders coating on the mold surface. The molten titanium for manufacturing hip joint was poured into steel mold. No reaction layer was formed on the surface of specimens fabricated steel mold coated with $Y_2O_3$ powder.

Effects of Si Addition on the Microstructure and Properties of Cr-Al alloy for High Temperature Coating (고온 코팅용 Cr-Al합금의 미세조직 및 특성에 미치는 Si 첨가의 영향)

  • Kim, Jeong-Min;Kim, Il-Hyun;Kim, Hyun-Gil
    • Korean Journal of Materials Research
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    • v.29 no.1
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    • pp.7-10
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    • 2019
  • Cr-Al alloys are attracting attention as oxidation resistant coating materials for high temperature metallic materials due to their excellent high temperature stability. However, the mechanical properties and oxidation resistance of Cr-Al alloys can be further enhanced, and such attempts are made in this study. To improve the properties of Cr-Al alloys, Si is added up to 5 wt%. Casting specimens with different amounts of Si content are prepared by a vacuum arc remelting method and isothermally heated under steam conditions at $1,100^{\circ}C$ for 1 hour. The as-cast microstructure of low Si alloys is mainly composed of only a Cr phase, while $Al_8Cr_5$ and $Cr_3Si$ phases are also observed in the 5 % Si alloy. In the high Si alloy, only Cr and $Cr_3Si$ phases remain after the isothermal heating at $1,100^{\circ}C$. It is found that Si additions slightly decrease the oxidation resistance of the Cr-Al alloy. However, the microhardness of the Cr-Al alloy is observed to increase with an increasing Si content.

Microstructural Control of Al-Sn Alloy with Addition of Cu and Si (Cu와 Si 첨가에 의한 Al-Sn 합금의 미세조직 제어)

  • Son, Kwang Suk;Park, Tae Eun;Kim, Jin Soo;Kang, Sung Min;Kim, Tae Hwan;Kim, Donggyu
    • Korean Journal of Metals and Materials
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    • v.48 no.3
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    • pp.248-255
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    • 2010
  • The effect of various alloying elements and melt treatment on the microstructural control of Al-Sn metallic bearing alloy was investigated. The thickness of tin film crystallized around primary aluminum decreased with the addition of 5% Cu in Al-Sn alloy, with tin particles being reduced in size by intervening the Ostwald ripening. With the addition of Si in Al-10%Sn alloy, the tin particles were crystallized with eutectic silicon, resulting in uniform distribution of tin particles. With the addition of Cu and Si in Al-Sn alloy, both the tensile strength and yield strength increased, with the increasing rate of yield strength being less than that of tensile strength. Although the Al-10%Sn-7%Si alloy has similar tensile strength compared with Al-10%Sn-5%Cu, the former showed superior abrasion resistance, resulting from preventing the tin particles from movement to the abrasion surface.