• Title/Summary/Keyword: AC4C

Search Result 613, Processing Time 0.026 seconds

Numerical Study on Thermal Deformation of AC4C and AC7A Casting Material (AC4C와 AC7A 주조재의 열변형 수치해석적 연구)

  • Yoon, Hee-Sung;Oh, Yool-Kwon
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.20 no.5
    • /
    • pp.541-546
    • /
    • 2011
  • This study was numerically investigated on thermal deformation of AC4C and AC7A aluminum alloy casting material for manufacturing the automobile tire mold. The metal casting device was used in order to manufacture the mold product of automobile tire at the actual industrial field. The temperature distribution and the cooling time of these materials were numerically calculated by finite element analysis. Thermal deformation with stress distribution was also calculated form the temperature distribution results. The thermal deformation was closely related to the temperature difference between the surface and inside of the casting. As shown by numerical analysis result, the thermal deformation of AC7A casting material became higher than AC4C casting material. In addition, the results of displacement and stress distributions appeared to be larger at the center parts of casting than on its sides because of the shrinkage caused by the cooling speed difference.

A Study for Characteristic and Manufacturing of Porous Ni/AC4C and Ni-Cr/AC4C Composites (다공질 Ni 및 Ni-Cr으로 강화한 AC4C 복합재료의 제조 및 특성연구)

  • Kim, Young-Hyun;Kim, Eok-Soo;Yeo, In-Dong;Lee, Kwang-Hak
    • Journal of Korea Foundry Society
    • /
    • v.20 no.1
    • /
    • pp.21-28
    • /
    • 2000
  • Ni and Ni-Cr porous metals which are estimated to be easy to fabricate by squeeze casting are used as strengtheners for composite materials. As a matrix material, Al-7%wtSi-0.3 wt%Mg(AC4C) has been used. In case of Ni/AC4C and Ni-Cr/AC4C composite, $750^{\circ}C$ melt temperature and minimum 25 MPa squeezing pressure are needed to produce sound composite materials. The observation of interfacial reaction zone at various heat treatment condition showed that solutionizing temperature of above 520^{\circ}C$, the interfacial reaction zone increased proportionally with increasing heat treatment tim and reaction products formed by interfacial reaction are mainly composed of $Al_3Ni$ and $Al_3Ni_2$ phases. The tensile strength of Ni/AC4C and Ni-Cr/AC4C composite is lower than the matrix metal and this can be explained by the brittle intermetallic compounds formed at the interface of Ni and Ni-Cr reinforcements. But the properies of hardness, wear resistance and thermal expansion are better than the matrix due to the strengthening effect of Ni-Cr porous metals.

  • PDF

Characterization of the Ni and Ni-Cr Porous Metal Reinforced AC4C Matrix Composites Fabricated by Squeeze Casting (용탕단조법에 의한 Ni, Ni-Cr 다공질 발포금속 강화 AC4C 합금기 복합재료에 관한 연구)

  • Kim, Eok-Soo
    • Journal of Korea Foundry Society
    • /
    • v.25 no.2
    • /
    • pp.80-87
    • /
    • 2005
  • The microstructure and mechanical property of the Ni and Ni-Cr porous metal reinforced AC4C matrix composites fabricated by squeeze casting were investigated. In this study Ni, Ni-Cr porous metals which are estimated to be easy to fabricate by squeeze casting are used as strengtheners for composite materials. As a matrix material, Al-7wt.%Si-0.3wt.%Mg(AC4C) has been used. In case of Ni/AC4C and Ni-Cr/AC4C composite, $750^{\circ}C$ melt temperature and minimum 25MPa squeezing pressure are needed to produce sound composite materials. The observation of interfacial reaction zone at various heat treatment condition shows that atsolutionizing temperature of above $520^{\circ}C$, the interfacial reaction zone increases proportionally with heat treatment time and the reaction products formed by interfacial reactions are mainly composed by $Al_{3}Ni$ and $Al_{3}Ni_{2}$ phases.

A Review on AC Loss Characteristics of High $T_c$ Superconductors

  • Amemiya, N.;Jiang, Z.
    • Progress in Superconductivity and Cryogenics
    • /
    • v.8 no.4
    • /
    • pp.1-7
    • /
    • 2006
  • This paper reviews AC loss characteristics of high $T_c$ superconductors. The mechanisms of AC loss generation are explained briefly, and AC losses are classified by the magnetic field components which generate them. A couple of analytical formulae of AC losses, which are useful for simple and rough AC loss estimations, are presented. AC loss characteristics of single BSCCO multifilamentary conductors and single YBCO coated conductors are reviewed based on previous experimental and numerical studies. AC loss characteristics of those two types of practical high $T_c$ superconductors are compared with each other.

Characterization of the Ceramic Reinforced AC4C Matrix Composites Processed by Squeeze Casting (용탕단조법으로 제조된 AC4C 합금기 세라믹강화 복합재료의 특성연구)

  • Kim, Eok-Soo
    • Journal of Korea Foundry Society
    • /
    • v.25 no.2
    • /
    • pp.88-94
    • /
    • 2005
  • The microstructure and mechanical property of the ceramic reinforced AC4C matrix composites processed by squeeze casting were investigated. In this study Kaowool and Saffil fiber which are ceramic reinforcements are used as preform materials. As a matrix material, Al-7wt.%Si-0.3wt.%Mg(AC4C) has been used. In case of Kaowool and Saffil/AC4C composites, 7.5 MPa squeezing pressure and minimum 7.0% binder amount are needed to produce sound composite materials. The tensile strength of Kaowool/ AC4C composite is lower than the matrix metal and this can be explained by the melt unfilling due to formed cluster of Kaowool reinforcements. But the mechanical properties of hardness, wear resistance and thermal expansion are better than the matrix materials due to the strengthening effect of ceramic reinforcements.

A Stable Preservation of Extracellular Nonoccluded Virions from Autographa californica Nuclear Polyhedrosis Virus Infection (Autographa californica 핵다면체 바이러스의 세포외 미봉입비리온의 안전한 보존)

  • 이형환;이근광;이건주
    • Microbiology and Biotechnology Letters
    • /
    • v.18 no.6
    • /
    • pp.660-661
    • /
    • 1990
  • A stable preservation method of extracellular non-occluded virion of Autographa californica nuclear polyhedrosis virus (AcNPV) was studied. AcNPVL-1 strain infected to Spodoptera frugiperda cell line and then the culture media were centrifuged. After centrifugation the supernatant containing extracellular nonoccluded virions of the AcNPV was harvested and incubated at $4^{\circ}C$ . Even after the extracellular nonoccluded virions were incubated at $4^{\circ}C$ for about 11 years, the infectivity and multiplication property of the nonoccluded virions in the S. frugiperda cell line were normal. However the titers of the nonoccluded virions in TC-100 medium measured about 11 years ago decreased from $8.9 \times 10^7\; to \;3.8 \times 10^5$ pfu per ml. The AcNPV genome DNA fragment patterns from digestion with Hind11 and EcoRI restriction endonucleases did not change. The AcNPV nonoccluded virions were stable at $4^{\circ}C$ in the cultured medium of more than 10 years and the preservation of AcNPV nonoccluded virions at $4^{\circ}C$ is easy and useful for handling.

  • PDF

Fabrication of ACtA/$SiC_w$ composite by squeeze casting (I) (용탕 단조법에 의한 AC4A/Si$C_w$복합재료 제조에 관한 연구 (I))

  • Moon, Kyung-Cheol;Lee, Jun-Hee
    • Korean Journal of Materials Research
    • /
    • v.2 no.6
    • /
    • pp.461-467
    • /
    • 1992
  • A fabrication process for SiC whisker preform reinforced AC4A Al composites is being developed. The Al alloy used as the matrix in this study is AC4A. SiC whisker preform made by Tokai Carbon Co. Ltd. Shizuoka, Japan were used. These consisted of $\beta$-type single crystals 0.1 ~ 10${\mu}$m in diameter and 20~10${\mu}$m in length. The most adequate fabrication condition was that whisker preform was preheated up to 750~80$0^{\circ}C$, set into a mould preheated to ~40$0^{\circ}C$, molten Al alloy heated to ~80$0^{\circ}C$ and applied pressure 75MPa. And Si$C_w$reinforced AC4A composite was advanced above twice than AC4AI/M. Also it was not large effect by pressure at Si$C_w$ 20v/o.

  • PDF

Static and Dynamic Characteristics of AC4C Aluminum Alloy (AC4C 알루미늄 합금의 정적 및 동적 특성)

  • Kwon, Y.G.;Ju, W.K.;Song, J.I.
    • Proceedings of the KSME Conference
    • /
    • 2007.05a
    • /
    • pp.220-225
    • /
    • 2007
  • The mechanical characteristics of AC4C Aluminum Casting Alloy were investigated by tensile test and impact test. Based on the tensile test' s result, we found that the yield strength of a high speed was about 10% higher than that of a low speed test and the maximum rupture strain mostly occurred in low speed tensile test. The impact energy of curved surface specimen was higher than that of plane surface specimen that can be measured in impact test.

  • PDF

Chemical Species of Uranium and Vanadium in Organic Acid Media (유기산용액에서 우라늄과 바나듐의 화학종에 관한 연구)

  • Ki-Won Cha;Cong-Sik Yu;Jong-Hun Kim
    • Journal of the Korean Chemical Society
    • /
    • v.29 no.6
    • /
    • pp.615-622
    • /
    • 1985
  • The chemical species formed by uranium and vanadium and their equilibria have been investigated in the various concentrations of oxalic and acetic acids by the ion exchange chromatography and UV-Vis spectrophotometry. Uranyl and vanadyl ions seem to be form the complex as $UO_2(C_2O_4)_2=$, $UO_2(C_2O_4)_3^{4-}$ and $VO_2(C_2O_4)-2^{3-}$ respectively in the concentration range of 0.005∼0.05M oxalic acid concentration. In the case of acetic acid the equilibria of $UO_2^{2+}+3Ac^-=UO_2(Ac)_3^-$ and $VO_2^++2Ac^-=VO_2(Ac)_2^-$ were existed individually according to the increase of acetic acid concentration.

  • PDF

Fabrication of AC4A/$SiC_w$composite by squeeze casting(II) (용탕단조법에 의한 AC4A/$SiC_w$복합재교 제조에 관한 연구(ll)-가압력 및 시효특성-)

  • Mun, Gyeong-Cheol;Lee, Chun-Hui
    • Korean Journal of Materials Research
    • /
    • v.3 no.6
    • /
    • pp.606-613
    • /
    • 1993
  • This was studied about aging characteristic of AC4A/$SiC_{w}$ 10-30v/o reinforced composite. Aging hardenability was decreased $SiC_{w}$ 30% > 10% > 20%. Aging hardening of T6 treatmented composite was higher absolute value than AC4A I/M material. And this results indicated initial hardening phenomenon according to increase $SiC_{w}$ volume fraction. Reinforced effect by pressure was the same effect as before aging treatment and the best condition pressure at 75MPa. Similar to reinforced effect according to $SiC_{w}$ volume fraction was 30 % > 10 % > 20 %. In case of pressure is low, whisker is not break the same time press with base metal after wetting. After it is wetting with base metal, a part transformed or wetting part break and whisker maintain original shape or a part transformed on the otherhand, in case of pressure is high, whisker is break in same time it was not against pressure and whisker's shape is near a polygon or spherical shape.

  • PDF