• Title/Summary/Keyword: alloying effect

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Effects of Mg and Si on Microstructure and Mechanical Properties of Al-Mg Die Casting Alloy (Al-Mg 계 다이캐스팅 합금의 미세조직 및 기계적 성질에 미치는 Mg 및 Si의 영향)

  • Cho, Jae-Ik;Kim, Cheol-Woo
    • Journal of Korea Foundry Society
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    • v.32 no.5
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    • pp.219-224
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    • 2012
  • The effects of Mg and Si contents on the microstructure and mechanical properties in Al-Mg alloy (ALDC6) were investigated. The results showed that phase fraction and size of $Mg_2Si$ and $Al_{15}(Fe,Mn)_3Si_2$ phase in the microstructure of Al-Mg alloy were increased as the Mg and Si contents were raised from 2.5 to 3.5 wt%. With Si content of 1.5 wt%, freezing range of the alloy was significantly reduced and solidification became more complex during the final stage of solidification. While there was no significant influence of Mg contents on mechanical properties, Si contents up to 1.5 wt%, strongly affected the mechanical properties. Especially elongation was reduced by about a half with more than 1.0 wt%Si in the alloy. The bending and impact strength were decreased with increased amount of Si in the alloy, as well. The lowered mechanical properties are because of the growth of particle shaped coarse $Mg_2Si$ phase and precipitation of the needle like $\beta$-AlFeSi in the microstructure at the last region to solidify due to presence of excess amount of Si in the alloy.

A Study on Forging Characteristic of Non-Heat Treated Micro-Alloyed Steel Using Finite Element Analysis (유한요소해석을 통한 비조질강 성형 특성 분석)

  • Kwon, Yong-Nam;Kim, S.W.;Lee, Y.S.;Lee, J.H.
    • Transactions of Materials Processing
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    • v.15 no.8 s.89
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    • pp.609-614
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    • 2006
  • Micro-alloyed steels(MA steels) for cold forging was developed to replace the usual quenched and tempered steel. MA steels have several advantages over the conventional quenched and tempered carbon steels. First of all, energy consumption could be lowered due to the elimination of spherodizing annealing and quenching/tempering heat treatment. Also, bending during quenching could be avoided when MA steels are applied for manufacturing of long fastener parts. However, larger amount of load is exerted on the dies compared than in the case of conventional mild steels, which might lead to the earlier fracture of dies, when MA forging steels are applied in forging practice. Therefore, die lift could be a critical factor to determine whether HA forging steels could be widely applied in cold forging practice. In the present study, authors have investigated the forging characteristics of non-heat treated micro-alloyed steel by using a series of experimental and numerical analyses. Firstly, microstructural features and its effect on the deformation behavior have been studied. Numerical analysis has been done on the forging of guide rod pin to investigate for the optimization of forging process and die stress prediction.

Electrodes for contact electric welding of aluminium alloys

  • Bondar, M.P.;Moon, J.G.
    • Proceedings of the KWS Conference
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    • 1997.10a
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    • pp.184-193
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    • 1997
  • Aluminium and aluminium alloys have the high electrical and heat conductivity. It gives rise to difficulties for a choice of electrodes material for their contact electric welding. This paper describes the investigations performed to solve the above problem. The purpose of this investigation was to obtain dispersion-hardening alloys by the internal oxidation method, to optimize their contents and treatment modes, to produce electrodes of these alloys and to test them. The strengthing effect of alloys with oxide particles depends on their size stability at high temperatures. Despite of the fact, that oxides are the most stable of all the non-metallic phases their coagulation takes place. Based on the early results, we chose two types of alloys, first No. 1 Cu - 0,4%Al and second No. 2 Cu - 0,2%Be for production of electrodes. These alloys had not additional alloying elements. These alloys were prepared as 1 mm plates and flake-formed 200 m thick, and also No. 1 as a powder of size 100 mkm (received from Korea). The large samples for electrodes were produced by three methods : explosive welding method, dynamic one including the explosion compression of electrode blank and the quasi-dynamic method including the high-speed compression of dense briquest and the further hot extrusion of a rod.

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Variation of Fluidity and Mechanical Properties of Al-Mg Alloys with the Addition of Si, Mn, and Zn (합금원소 Si, Mn, Zn 첨가에 따른 Al-Mg 합금의 유동도 및 기계적 성질 변화)

  • Kim, Jeong-Min;Seong, Ki-Dug;Jun, Joong-Hwan;Kim, Ki-Tae;Jung, Woon-Jae
    • Journal of Korea Foundry Society
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    • v.24 no.3
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    • pp.138-144
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    • 2004
  • Effects of alloying elements such as Si, Mn, Zn on the fluidity and mechanical properties of high ductility Al-Mg based alloys were investigated. The fluidity of alloys was evaluated using a vacuum suction fluidity test, and Si addition was observed to increase the fluidity of AI-Mg binary alloys substantially while Zn somewhat decreased the fluidity. However, both the strength and ductility were significantly deteriorated by the Si additions. It was observed that a small amount of Mn addition to Al-Mg alloy increased the tensile strength effectively without losing much ductility but the effect of Zn addition on the strength was relatively small.

Microstructural Characteristics and Thermal Expansion Coefficient of AlN-Cu Nanocomposite Materials Prepared by Solid State Processing (고상공정에 의해 제조된 AIN-Cu 나노복합재료의 조직 특성과 열팽창계수 측정에 관한 연구)

  • Lee, Gwang-Min;Lee, Ji-Seong;Lee, Seung-Ik;Kim, Ji-Sun;Weissgaerber, T.;Kieback, B.
    • Korean Journal of Materials Research
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    • v.11 no.10
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    • pp.863-868
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    • 2001
  • The present study was carried out to investigate the effect of MA processing variables on the microstructural properties of composite powders and the coefficient of thermal expansion of pulse electric current sintered AlN-Cu powder compacts. The AlN-Cu powders had a size of less than 15 $\mu\textrm{m}$ with 25 nm size of copper crystallite after MA 32 hours. The finely distributed AlN-Cu powder compacts were completely achieved after PECS. The residual oxygen was considerably removed after hydrogen reduction treatment. The residual carbon was completely removed to 97%. The CTE of AlN-Cu powder compacts showed a good consistency with Kingery-Tuner model when the volume fraction of copper was less than 60%. When it was more than 60%, the CTE had a good agreement with Series model.

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The effects of rolling process on microstructures and high temperature tensile properties of Al-Mg alloy (Al-Mg합금의 압연변수에 다른 미세구조의 변화와 고온인장특성)

  • Kim, Tae-Kue;Jeon, C.H.;Kwun, S.I.;Park, Jong-Woo
    • Journal of the Korean Society for Heat Treatment
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    • v.10 no.2
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    • pp.81-92
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    • 1997
  • The effect of alloying elements, precipitate size, its distribution, and dislocation substructure resulted from warm rolling or cold rolling in the superplastic Al-Mg alloy system was investigated. One of the major requirements for fine structure superplasticity is that the grain size should be very small. Fine grain structure is controlled by the dislocation substructure and the dynamic recrystallization during hot or warm working. The recovery of Al-Mg base alloys was constrained resulting in relatively high dislocation density when the alloys were warm rolled. In particular, Al-Mg-Zr alloy exhibited the smallest sub-grain size among Al-Mg alloys containing Mn, Cu, Zr as a third element. The Al-Mg-Mn alloy cold rolled 80% after hot rolling showed the maximun strain rate sensitivity exponent, m, of 0.75 under strain rate of $7.1{\times}10^{-4}/s$ at $500^{\circ}C$. The elongation of the alloys was limited in spite of high m values due to large dispersoids containing appreciable amount of Fe impurities.

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The Effect of Zr Addition on AM50 Mg Alloys Foam Metals (AM50 Mg합금 발포금속의 제조와 지르코늄 첨가 영향)

  • Kim, Byeong-Gu;Tak, Byeong-Su;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.30 no.6
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    • pp.217-223
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    • 2010
  • Foamed metal has become an attractive material, which has unique physical, thermal, acoustic, damping and mechanical properties, because large amount of pores are distributed in the metal matrix. Therefore, metal foam can be used for the light weight application in automotive, locomotive, aerospace fields. Aluminum foams have been developed successfully and will be employed in the next generation of energy absorption boxes. Magnesium alloys are most eligible candidate to substitute aluminum alloy, especially for lower density and higher damping properties in wide industrial fields. Magnesium alloy foams are expected to be particularly advantageous due to two thirds the density of aluminum. However, foaming magnesium have been weakness of high activity, difficult processing and very dangerous. In order to upgrade this problem, AM50 magnesium alloy which has better characteristic is safe to use through foaming time and alloying element in this study.

Effect of Foaming Temperature on Cell Structure of 606X Series Aluminum Alloy Metallic Foams (Foaming 온도에 따른 606X계 발포 알루미늄의 제조 특성)

  • Song, Yeong-Hwan;Park, Soo-Han;Jeong, Min-Jae;Kang, Kwang-Jung;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.28 no.2
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    • pp.79-84
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    • 2008
  • Metal foam is one of the most interesting materials with various multi-functional properties such as light weight, energy absorption, high stiffness and damping capability. Among them, energy absorption property has keen interests in the field of automotives for passenger protection. Nowadays, researches about pore size and porosity control of the foam are increased to correspond them. However, though energy absorption properties are improved, these results are not cost-effective process. In present research, however, as a part of improving the energy absorption property of metallic foams, 606X aluminum alloy was used for cell wall material which has higher strength than pure aluminum. And its morphological features are characterized. As a results, porosity and pore size are uniformity distribution with increasing foaming temperature in the case of 6061 alloy foams. 6063 alloy foam specimens have opposite tendency because of the influence of alloying element and viscosity of the molten melt.

Effects of Alloying Elements on the Tensile Strength and Electrical Conductivity of Cu-Fe-P Based Alloys (Cu-Fe-P계 합금의 강도 및 전기전도도에 미치는 첨가 원소의 영향)

  • Kim, Dae-Hyun;Lee, Kwang-Hak
    • Korean Journal of Materials Research
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    • v.20 no.2
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    • pp.65-71
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    • 2010
  • In this study, the effect of Sn and Mg on microstructure and mechanical properties of Cu-Fe-P alloy were investigated by using scanning electron microscope, transmission electron microscope, tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases in order to satisfy characteristic for lead frame material. It was observed that Cu-0.14wt%Fe-0.03wt%P-0.05wt%Si-0.1wt%Zn with Sn and Mg indicates increasing tensile strength compare with PMC90 since Sn restrained the growth of the Fe-P precipitation phase on the matrix. However, the electrical conductivity was decreased by adding addition of Sn and Mg because Sn was dispersed on the matrix and restrained the growth of the Fe-P precipitation. The size of 100 nm $Mg_3P_2$ precipitation phase was observed having lattice parameter $a:12.01{\AA}$ such that [111] zone axis. According to the results of the study, the tensile strength and the electrical conductivity satisfied the requirements of lead frame; so, there is the possibility of application as a substitution material for lead frame of Cu alloy.

Effect of Alloying Elements of Mn and Ni on the Pitting Corrosion Resistance of 22Cr Lean Duplex Stainless Steel (22Cr 린 듀플렉스 스테인리스강의 공식저항성에 미치는 Mn과 Ni 첨가의 영향)

  • Ahn, Y.S.;Bae, K.K.
    • Journal of Power System Engineering
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    • v.16 no.5
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    • pp.76-82
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    • 2012
  • Duplex stainless steels have the dual microstructure of austenite and ferrite phases. This steel exhibits generally a high corrosion resistance and higher mechanical strength compared with austenitic stainless steels. The steels used in the investigation have the chemical composition of Fe-22Cr-xNi-yMn-0.2N in which the contents of Ni and Mn were varied with maintaining the equal [Ni/Cr] equivalent. The fraction of ferrite phase was increased with the increase of annealing temperature. The impact factor of Mn element on the [Ni] equivalent was amended on the basis of the results of the investigation. 4Mn-2Ni alloy showed the highest pitting corrosion resistance. The fraction ratio, grain size and misorientation angle between grains were measured, and the correlation with pitting potential was investigated.