• Title, Summary, Keyword: Al-alloy

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Application development of 7050Al alloy in small arms. (소화기용 7050 Al합금소재의 적용성 개발)

  • 김헌규;최중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1093-1097
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    • 1996
  • The Substitution development of 7075-T6 Al alloy to 7050-T74 Al alloy in small arms to improve anti-stress corrosion cracking was processed along with mass productivity consideration. To meet 7050 Al alloy material characteristics Indirect extrusion type was adopted and local heating above recrystalization temperature in forging process had to be avoided. The T74 aging treatment was 12$0^{\circ}C$ -6hrs and 175$^{\circ}C$ -12hrs and was appropriate for both machanical and anti-cohesion properties. In accessment of field application test 7050Al alloy made parts of small arms showed equivalent or better performance than 7075 Al alloy.

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An Experimental Study on the Impact Characteristics of Surface Hardened Al 5052-H34 Alloy (표면처리된 알루미늄 5052-H34 합금의 층격특성에 관한 실험적 연구)

  • 손세원;김희재;이두성;홍성희
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.3
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    • pp.178-186
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    • 2003
  • In order to investigate the fracture behaviors (penetration modes) and the resistance to penetration during ballistic impact of Al 5052-H34 alloy laminates, cold-rolled Al 5052-H34 alloy laminates, anodized Al 5052-H34 alloy laminates, and anodized Al 5052-H34 alloy after cold-rolling, a ballistic testing was conducted. In general, superior armor materials are brittle materials which have a high hardness. Ballistic resistance of these materials was measured by a protection ballistic limit (V$_{50}$), a statistical velocity with 50% probability fur incompletete penetration. Fracture begaviors and ballistic tolerance, described by penetration modes, ate observed from the results from the results of V$_{50}$ test and Projectile Through Plates (PTP) test at velocities greater than V$_{50}$, respectively. PTP tests were conducted with 0$_{\circ}$obliquity at room temperature using 5.56mm ball projectile. V$_{50}$ tests with 0$_{\circ}$obliquity at room temperature were concucted with projectiles that could achieve neat or complete penetration during PTP tests. Surface hardness, resistance to penetration, and penetration modes of Al 5052-H34 alloy laminates are compared to those of cold-rolled Al 5052-H34 alloy laminates and anodized Al 5052-H34 alloy laminates and anodized Al 5052-H34 cold-rolled alloy.

The Study on the Corrosion Characteristics of Al-Alloy Shell for Cooler (알루미늄합금 원통냉각기의 부식 특성에 관한 연구)

  • 임우조;김성진;윤병두
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.39 no.2
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    • pp.152-157
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    • 2003
  • Most Recently, with rapid development in marine industries such as marine structures and ship, there occurs much interest in the study of corrosion characteristics which play an important role in design of cooling water system like heat-exchanger. Especially, as operating environment of fresh cooling water system in vessels is acidified, this system is seriously corroded. In this study, to study on the corrosion characteristics of Al-alloy shell for cooler, the electrochemical polarization test of materials for the marine fresh water cooler such as Al-alloy, Cu and naval brass was carried out in fresh water. And thus the polarization resistance and anodic polarization behavior of Al-alloy, Cu and naval brass are investigated. Also, galvanic corrosion characteristics of Al-alloy coupled with Cu and naval brass is considered. The main results obtained are as follows ; (1) The current density of corrosion is high in order of Al-alloy > naval brass > Cu (2) As anodic potential increases, the corrosion resistance of naval brass is better than that of Cu. (3) The galvanic corrosion of Al-alloy coupled with Cu and naval brass is activated than corrosion of Al-alloy.

The Changes of the Shape and Particle Size Distribution of δ' Phase on Ageing in Al-Li-( Cu, Zr) Alloys (Al-Li-( Cu, Zr) 합금에서 시효에 따른 δ' 상의 형상 및 입자크기분포의 변화)

  • Woo, K.D.;Cho, H.K.
    • Journal of the Korean Society for Heat Treatment
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    • v.7 no.2
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    • pp.96-102
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    • 1994
  • The present work was aimed to examine the changes of the shape and particle size distribution(PSD) of ${\delta}^{\prime}$ particles on ageing in Al-Li-(Cu, Zr) alloys which had low density, high specific strength and stiffness, Increasing ageing time and temperature resulted in particles whose aspect ratio tended toward 1. The aspect ratio of ${\delta}^{\prime}$ particles was not dependent upon the ageing temperature and time in Al-Li-Cu alloy but was dependent upon them in Al-Li-Zr alloy. The PSD of ${\delta}^{\prime}$ particles in Al-Li-Zr alloy skewed to the right hand compared with that in Al-Li-Cu alloy, because $Al_3Zr$ phase in Al-Li-Zr alloy formed before ageing promoted the precipitation and growth of ${\delta}^{\prime}$ phase. Therefore, the PSD of the ${\delta}^{\prime}$ particles was found to be affected by the presence of $Al_3Zr$ particles. The growth rate of ${\delta}^{\prime}$ phase was not affected by the existence of the third transition phase $T_1$ formed by the addition of Cu in Al-Li alloy but was affected by the existence of $Al_3Zr$ formed by the addition of Zr in Al-Li alloy.

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Effects of Si Content and Melt Treatment on the Fluidity of Al-Si Alloy during Squeeze Casting (알루미늄 - 규소 합금의 용탕단조시 유동도에 미치는 규소 함량 및 용탕 처리의 영향)

  • Lee, Hag-Ju;Kwon, Hae-Wook
    • Journal of Korea Foundry Society
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    • v.26 no.6
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    • pp.241-248
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    • 2006
  • The effects of silicon content and melt treatment on the fluidity of Al-Si alloys during squeeze casting were investigated. The fluidity of Al-3.0 wt%Si alloy was found to be lower than that of Al-1.0 wt%Si and the fluidity of the alloy with more than 3.0 wt%Si increased with the silicon content upto 13.0 wt% and rather decreased with15.0 wt%. The fluidity was also increased by the separated treatment of grain refinement or eutectic modification, and even more by the simultaneous treatment of both. The fluidity of hypereutectic alloy was increased by the refinement of primary silicon particle.

Fracture and Wear Characteristics of Al-Si alloy used for Compressor (컴프레서용 Al-Si 합금의 파괴 및 마모 특성)

  • 김재훈;김덕회
    • Tribology and Lubricants
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    • v.15 no.2
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    • pp.141-149
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    • 1999
  • Fracture, fatigue and wear characteristics of Al-Si alloy used for compressor are experimentally studied. Plane strain fracture toughness test is carried out using three point bending specimen. Fatigue test is performed under constant loading condition and wear test is carried out as a function of sliding velocity and applied load. To obtain the crack propagation characteristics and wear mechanism of Al-Si alloy, fracture and worn surfaces are investigated using SEM. It is verified that fracture and fatigue strength of Al-Si alloy are improved by the fine microstructure of alloy. The wear behavior and specific wear amount of Al-Si alloy are not dependent on the microstructure but on a function of the silicon content. Anodizing on the surface of Al-Si alloy, surface hardness and wear characteristics are improved.

Effect of Al Addition on the Precipitation Behavior of a Binary Mg-Zn Alloy

  • Kim, Ye-Lim;Tezuka, Hiroyasu;Kobayashi, Equo;Sato, Tatsuo
    • Korean Journal of Materials Research
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    • v.22 no.3
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    • pp.111-117
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    • 2012
  • The effect of Al addition on the precipitation behavior of a binary Mg-Zn alloy was investigated based on the changes in the morphology, distribution and element concentration of precipitates formed during aging treatment. The as-cast Mg-6.0 mass%Zn (Mg-6Zn) and Mg-6.0 mass%Zn-3.0 mass%Al (Al-added) were homogenized at 613 K for 48 h and at 673 K for 12 h; they were then solid solution treated at 673 K for 0.5 h and 1 h, respectively. The Mg-6Zn and Al-added alloys were aged at 403 K and 433 K. The peak hardness of the Al-added alloy was higher than that of the Mg-6Zn alloy at each aging temperature. Rod-like, plate-like, blocky, and lath-like precipitates were observed in the Al-added alloy aged at 433 K for 230.4 ks, although the rod-like and plate-like precipitates were observed in the TEM microstructure of the Mg-6Zn alloy aged at 433 K for 360 ks. Moreover, the precipitates in the Al-added alloy were refined and densely distributed compared with those in the Mg-6Zn alloy. The Cliff-Lorimer plots obtained by the EDS analysis of the rod-like ${\beta}_1^'$ and plate-like ${\beta}_2^'$ phases in the Al-added alloy peak aged at 433 K for 230.4 ks were examined. It was confirmed that the ${\beta}_2^'$ phases had higher concentration of solute Al atom than was present in the ${\beta}_1^'$ phases, indicating that the properties of precipitates can be changed by Al addition.

The corrosion phenomena of AlCu films after reactive ion etching (반응성 이온 식각후 AlCu막의 부식현상)

  • 김창일;권광호;김상기;장의구
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.252-255
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    • 1996
  • Cl-based gas chemistry is generally used to etching for Al alloy metallization. After the etching of Al alloy with Cl-based gas plasma, residual chlorine on Al alloy reacts with $H_2O$ due to air exposure and results in Al corrosion. In this study, the corrosion Phenomena of Al were examined with XPS(X-ray photoelectron spectroscopy) and SEF(Scanning electron microscopy). It was confirmed that chlorine mainly existed at the grain boundary of Al alloy after plasma etching of Al alloy with Cl-based gas chemistry and Al corrosion was largely generated at the grain boundary of Al a1loy. And residual chlorine was passivated by sulfur and fluorine which were generated by SF$_{6}$ plasma. These effects of passivation reduced the Al corrosion due to air exposure.e.

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Thermal Stability and Dry Sliding Wear Behavior of Ultra-Fine Grained 6061 Al Alloy Processed by the Accumulative Roll-Bonding Process (누적압연접합 공정에 의해 제조된 초미세립 6061 Al 합금의 열적 안정성과 건식 미끄럼 마멸 거동)

  • Kim Y.S.
    • Transactions of Materials Processing
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    • v.14 no.1
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    • pp.71-77
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    • 2005
  • Thermal stability and dry sliding wear behavior of ultra-fine grained 6061 Al alloy fabricated by an accumulative roll-bonding (ARB) process have been investigated. After 4 ARB cycles, an ultra-fine grained microstructure of the 6061 Al alloy composed of grains with average size of 500nm, and separated mostly by high-angle boundaries was obtained. Though hardness and tensile strength of the ARB processed Al alloy increased with ARB cycles up to 4 cycles, the processed alloy exhibited decreased ductility and little strain hardening. Thermal stability of the ARB-processed microstructure was studied by annealing of the severely deformed alloy at $423K{\sim}573K$. The refined microstructure of the alloy remained stable up to 473K, and the peak aging treatment of the alloy at 450K for 8 hrs increased the thermal stability of the alloy. Sliding-wear rates of the alloy increased with the number of ARB cycles in spite of the increased hardness with the cycles. Wear mechanisms of the ultra-fine grained alloy were investigated by examining worn surfaces, wear debris, and cross-sections by a scanning electron microscopy (SEM).

Effects of Pressure, Superheat and Si Content on the Fluidity of Al-Si Alloy during Squeeze Casting (Al-Si 합금의 용탕 단조시 유동도에 미치는 압력, 과열 및 규소 함량의 영향)

  • Lee, Hag-Ju;Jung, Ki-Hwan;Kwon, Hae-Wook
    • Journal of Korea Foundry Society
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    • v.26 no.3
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    • pp.133-139
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    • 2006
  • The effects of applied pressure, superheat and silicon content on the fluidity of Al-Si alloy during squeeze casting were investigated. The Fluidity of Al-7.0wt%Si alloy during squeeze casting was increased with applied pressure up to 60 MPa, meanwhile it rather decreased beyond that. Therefore, the optimum squeeze casting pressure was 60 MPa. The fluidity was increased with superheat up to $150^{\circ}C$. On the other hand, it rather decreased at the superheat of $200^{\circ}C$. The fluidity of Al-Si alloy during squeeze casting was decreased with silicon content in the range of $0.0{\sim}3.0\;wt%$, increased in the range of $3.0{\sim}13.0\;wt%$. The fluidity of Al-15.0 wt%Si alloy was lower than that of Al-13.0 wt%Si alloy.