• Title, Summary, Keyword: Al-alloy

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Mechanical and Electrochemical Properties of Plasma Electrolytic Oxide Coatings on Aged Mg-Al alloy (플라즈마 전해 산화처리한 시효경화 Mg-Al 합금 피막의 기계적 및 전기화학적 특성)

  • Chang, Si-Young;Kim, Ye-Lim;Kim, Yang-Do
    • Korean Journal of Materials Research
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    • v.17 no.12
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    • pp.648-653
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    • 2007
  • Plasma electrolytic oxidation (PEO) treatment was performed on cast Mg-6 wt%Al alloy solution-treated at 693K for 16h and aged at 498K. The surface roughness, thickness, micro-hardness, wear and corrosion properties of coatings on solution-treated and aged Mg-6 wt%Al alloy were investigated. The coatings on aged Mg-6 wt%Al alloy had thinner layer and lower micro-hardness and wear resistance than the solution-treated Mg-6 wt%Al alloy. As the aging time increased, the thickness of coatings decreased while the surface roughness was almost no changed. In addition, the micro-hardness and wear property of coatings decreased with increasing the aging time unlike the uncoated Mg-6 wt%Al alloy showing the peak micro-hardness and the best wear property after aging for 16 h. However, the coatings on Mg-6 wt%Al alloy peak-aged for 16h revealed the best corrosion resistance in 3.5% NaCl solution, which was explained based on the microstructural characteristics.

Effect of the Microstructrure of Rapidly Solidified Al-Pb-Cu-Mg on the Wear ProPerty (급속응고된 Al-Pb-Cu-Mg 합금의 마모특성에 미치는 미세조직의 영향)

  • 김홍물
    • Journal of Korean Powder Metallurgy Institute
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    • v.7 no.1
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    • pp.12-18
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    • 2000
  • Effects of the microstrucrure of rapidy solidified Al-Pb-Cu-Mg alloys on the wear investigated. In order to overcome the miscility gap between Al and pb under equilibrium conditions, both in the solid and the liquid states, the alloy were rapidy solidifies to produce them in a segregation-free condition. Although the Pb particles showed relatively fine dispersion in the Al matrix in all the alloys by this process. the Al-16Pb alloy was found to have the most favorable microstructure with discretre with discrete Pb particles of abount 0.5 ${\mu}$m in size. With the addition of Cu and Cu-Mg to Al-16Pb, cellular structures were newly formed; not seen in the binary Al-Pb alloy. Wear properties of the Al-Pb binary alloys measured as a function of the sliding speen, sliding distance, and applied load showed that the Al-16Pb alloy has the best wear resistance, as expected from the fine microstructural features in this alloy. The were resistance of the alloy containing Cu-and Cu-Mg was higher than that of the Al-16Pvb alloy, due to matrix strengthening by precipitation hardeing. The wear mechanism was identified by examining the traces and wear debris.

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Fabrication and Mechanical Properties of $SiC_p/Al$ Composites by Pressureless Infiltration Technique (무가압침투법에 의한 $SiC_p/Al$ 복합재료의 제조 및 기계적 특성)

  • Jin, H.G.;Oh, M.S.;Kim, Y.S.
    • Journal of the Korea Society For Power System Engineering
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    • v.5 no.4
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    • pp.74-81
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    • 2001
  • The infiltration behavior of molten Al-alloy, microstructures, hardness, and the interfacial reactions of $SiC_p/Al$ composites fabricated by the pressureless infiltration technique were investigated. It was made clear that both the weight fraction of SiC reinforcement and additive Mg content considerably influenced on the infiltration behavior of the molten Al-alloy matrix. Complete infiltration of molten Al-alloy achieved under the conditions that weight fraction of SiC content is more than 30wt%, and additive Mg content is more than 9wt%. Interfacial region of Al-alloy matrix and SiC reinforcement phase, $Mg_2Si$ was formed by the reaction between Mg and SiC. Another reaction product AlN was also formed by the reaction between Al-alloy matrix and gas atmosphere nitrogen.

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Effects of heat treatment on Fe-Al Alloy Layers Formed by Al Powder Spray (Al분말 분사에 의해 생성된 Fe-Al합금 피막층의 열처리에 따른 영향)

  • 양병모;박정직;박광정;박경채
    • Journal of Welding and Joining
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    • v.14 no.1
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    • pp.92-98
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    • 1996
  • Al-Fe alloy layers on heated steel sheet were made by Al powder spray for 30 minutes at $700^{\circ}C$, $800^{\circ}C$ and $1000^{\circ}C$, respectively. As a results, for alloy layers formed at $700^{\circ}C$ and $800^{\circ}C$, main phases were brittle phase $FeAl_3 and Fe_2Al_5$, hardnesses were very high (Hv 700~800), corrosion resistances were good and surfaces were smooth, but wear resistances were bad. For alloy layer formed at $1000^{\circ}C$, main phase was ductile phase $Fe_3Al$, hardness was low (Hv 300~400), corrosion and wear resistances were excellent, but surface was rough. Therefore, alloy layers that formed at $700^{\circ}C$ and $800^{\circ}C$ were heat treated at $1000^{\circ}C$ for 10 minutes for the purpose of smooth surface and excellent wear resistance in this study. It was investigated that brittle phase $FeAl_3 and Fe_2Al_5$ of alloy layers fromed by Al powder spray at $700^{\circ}C$ and $800^{\circ}C$ turn into ductile phase $Fe_3Al$ by heat treated at $1000^{\circ}C$ for 10 minutes without changing smooth surface. It was concluded that the alloy layers formed by Al powder spray on heated steel sheet at $700^{\circ}C$ and $800^{\circ}C$ for 30 minutes and heat treated at $1000^{\circ}C$ for 10 minutes were excellent on wear and smooth surface.

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Processing of Nano-Sized Metal Alloy Dispersed $Al_2O_3$ Nanocomposites

  • Oh, Sung-Tag;Seok Namkung;Lee, Jai-Sung;Kim, Hyoung-Seop;Tohru Sekino
    • Journal of Korean Powder Metallurgy Institute
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    • v.8 no.3
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    • pp.157-162
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    • 2001
  • An optimum route to fabricate the ferrous alloy dispersed $Al_2O_3$ nanocomposites such as $Al_2O_3$/Fe-Ni and $Al_2O_3$/Fe-Co with sound microstructure and desired properties was investigated. The composites were fabricated by the sintering of powder mixtures of $Al_2O_3$ and nano-sized ferrous alloy, in which the alloy was prepared by solution-chemistry routes using metal nitrates powders and a subsequent hydorgen reduction process. Microstructural observation of reduced powder mixture revealed that the Fe-Ni or Fe-Co alloy particles of about 20 nm in size homogeneously surrounded $Al_2O_3$, forming nanocomposite powder. The sintered $Al_2O_3$/Fe-Ni composite showed the formation of Fe$Al_2O_4$ phase, while the reaction phases were not observed in $Al_2O_3$/Fe-Co composite. Hot-pressed $Al_2O_3$/Fe-Ni composite showed improved mechanical properties and magnetic response. The properties are discussed in terms of microstructural characteristics such as the distribution and size of alloy particles.

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Effectiveness of SWNT in reducing the crack effect on the dynamic behavior of aluminium alloy

  • Selmi, Abdellatif
    • Advances in nano research
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    • v.7 no.5
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    • pp.365-377
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    • 2019
  • This paper investigates the effectiveness of Single Walled Carbon Nanotubes, SWNT, in improving the dynamic behavior of cracked Aluminium alloy, Al-alloy, beams by using a method based on changes in modal strain energy. Mechanical properties of composite materials are estimated by the Eshelby-Mori-Tanaka method. The influence of SWNT volume fraction, SWNT aspect ratio, crack depth and crack location on the natural frequencies of the damaged 3D randomly oriented SWNT reinforced Al-alloy beams are examined. Results demonstrate the significant advantages of SWNT in reducing the effect of cracks on the natural frequencies of Al-alloy beams.

Preparation of SiC-Al alloy Composite by Pressureless Powder Packing Forming Method (분말 충전 성형법을 이용한 SiC-Al Alloy 복합체의 제조)

  • 박정현;송준광;백승수;염강섭;강민수
    • Journal of the Korean Ceramic Society
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    • v.34 no.4
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    • pp.343-350
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    • 1997
  • To fabricate the ceramic/metal(SiC/ Al alloy) composite, SiC preform was prepared by Pressureless Powder Packing Forming Method and 6061 Al alloy was infiltrated into the preform. Uniform compact having an average pore size of 10 ${\mu}{\textrm}{m}$ and narrow pore size distribution was prepared. Phenolic resin solution(40 wt%) was penetrated into the SiC compact, and then the compact was preheated at the temperature of 120$0^{\circ}C$. The pore size distribution and the microstructure of the preform were not changed by preheating. An uniform microstructure without any crack in the preform was obtained in SiC-Al alloy composite. The infiltration of 6061. Al alloy into the preform began at the temperature of 130$0^{\circ}C$ and the amount of infiltration increased in proportion to the infiltration temperature and the soaking time. The increasement rate of the infiltration amount decreased after 3 h. As a result of the infiltration at 140$0^{\circ}C$ for 4 h, Al alloy was well distributed in the interparticle channels and the relative density of the composite was above 98%. The strength and the fracture toughness of the composite were 303 MPa and 21.65 MPam1/2, respectively.

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Aging model for Al-Mg-Si forged part (Al-Mg-Si 단조품의 시효 모델)

  • Kwon Y.-N.;Lee Y.-S.;Lee J.-H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.307-310
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    • 2005
  • Ageing behavior of the Al-Mg-Si alloy was modeled for the use of optimization of Al forging product. Typical precipitates of Al-Mg-Si alloy are a wide variety of metastable phases (e.g. GP zones, $\beta',\beta'$). These rod shaped particles take a role to hinder the dislocation movement. The precipitation sequence in Al-Mg-Si alloys is quite complex and the strength of precipitate particles differs with the ageing condition. In the present study, the ageing behavior of Al-Mg-Si alloy was investigated by using an industrial grade Al 6061 alloy forged product, which was a perform for an Al impeller for turbo charger. The precipitate hardening models by Esmaeili's approach were used for the analysis of ageing behavior.

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Interrelationship between Structure and Mechanical Properties of Al-Cu-Li-X(In,Be) Alloy (Al-Cu-Li-X(In,Be) 합금(合金)의 조직(組織)과 기계적성질(機械的性質)의 상호관계(相互關係))

  • Lee, Sung-Ho;Lee, Jong-Soo;Kim, Suk-Won;Woo, Kee-Do
    • Journal of Korea Foundry Society
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    • v.15 no.4
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    • pp.351-359
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    • 1995
  • The effects of In and Be additions on the aging behaviors and mechanical properties in the Al-Cu-Li alloy were investigated using the transmission electron microscope, the scanning electron microscope, hardness and tensile strength measurement. The aging is promoted and the double hardness peak is appeared by the addition of In and Be in the Al-Cu-Li alloy. The strength is increased, but the elongation and toughness are decreased by the addition of In in the Al-Cu-Li alloy. And the Al-Cu-Li-In-Be alloy has good combination with the strength, the elogation and toughness than Al-Cu-Li-In alloy.

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Study of Al-Alloy Foam Compressive Behavior Based on Instrumented Sharp Indentation Technology

  • Kim Am-Kee;Tunvir Kazi
    • Journal of Mechanical Science and Technology
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    • v.20 no.6
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    • pp.819-827
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    • 2006
  • The stress-strain relation of aluminum (Al) alloy foam cell wall was evaluated by the instrumented sharp indentation method. The indentation in a few micron ranges was performed on the cell wall of Al-alloy foam having a composition or Al-3wt.%Si-2wt.%Cu-2wt.%Mg as well as its precursor (material prior to foaming). To extract the stress-stram relation in terms of yield stress ${\sigma}_y$, strain hardening exponent n and elastic modulus E, the closed-form dimensionless relationships between load-indentation depth curve and elasto-plastic property were used. The tensile properties of precursor material of Al-alloy foam were also measured independently by uni-axial tensile test. In order to verify the validity of the extracted stress-strain relation, it was compared with the results of tensile test and finite element (FE) analysis. A modified cubic-spherical lattice model was proposed to analyze the compressive behavior of the Al-alloy foam. The material parameters extracted by the instrumented nanoindentation method allowed the model to predict the compressive behavior of the Al-alloy foam accurately.