• Title/Summary/Keyword: intermetallic

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Variations of Micro-Structures and Mechanical Properties of Ti/STS321L Joint Using Brazing Method (브레이징을 이용한 Ti/STS321L 접합체의 미세조직과 기계적 특성의 변화)

  • 구자명;정우주;한범석;권상철;정승부
    • Journal of Welding and Joining
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    • v.20 no.6
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    • pp.106-106
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    • 2002
  • This study investigated variations of micro-structures and mechanical properties of Ti / STS321L joint with various bonding temperature and time using brazing method. According to increasing bonding temperature and time, it was observed that the thickness of their reaction layer increased due So increasing diffusion rate and time. From the EPMA results, Ti diffused to the STS321L substrate according to increasing bending time to 30min. Hardness of bonded interface increased with increasing bonding temperature and time due to increasing their oxides and intermetallic compounds. XRD data indicated that Ag, Ag-Ti intermetallic compounds, TiAg and Ti₃Ag and titanium oxide, TiO₂were formed in interface. In tensile test, it was found that the tensile strength had a maximum value at the bonding temperature of 900℃ and time of 5min, and tensile strength decreased over bonding time of 5min. The critical thickness of intermetallic compounds was observed to about 30㎛, because of brittleness from their excessive intermetallic compounds and titanium oxide, and weakness from void.

Variations of Micro-Structures and Mechanical Properties of Ti/STS321L Joint Using Brazing Method (브레이징을 이용한 Ti/STS321L 접합체의 미세조직과 기계적 특성의 변화)

  • 구자명;정우주;한범석;권상철;정승부
    • Journal of Welding and Joining
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    • v.20 no.6
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    • pp.830-837
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    • 2002
  • This study investigated variations of micro-structures and mechanical properties of Ti / STS321L joint with various bonding temperature and time using brazing method. According to increasing bonding temperature and time, it was observed that the thickness of their reaction layer increased due So increasing diffusion rate and time. From the EPMA results, Ti diffused to the STS321L substrate according to increasing bending time to 30min. Hardness of bonded interface increased with increasing bonding temperature and time due to increasing their oxides and intermetallic compounds. XRD data indicated that Ag, Ag-Ti intermetallic compounds, TiAg and $Ti_3Ag$ and titanium oxide, $TiO_2$ were formed in interface. In tensile test, it was found that the tensile strength had a maximum value at the bonding temperature of $900^{\circ}C$ and time of 5min, and tensile strength decreased over bonding time of 5min. The critical thickness of intermetallic compounds was observed to about $30\mu\textrm{m}$, because of brittleness from their excessive intermetallic compounds and titanium oxide, and weakness from void.

Effects of Iron, Silicon and Zinc Contained in Molten Aluminum on Aluminizing of Cast Iron (주철 소지상에 용융알루미늄 도금시 철 규소 및 아연의 영향)

  • Choi, Chong-Sool;Moon, Sung-Wuck
    • Journal of the Korean institute of surface engineering
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    • v.20 no.4
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    • pp.144-153
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    • 1987
  • In the case of dipping the Ni-Resist cast iron into molten aluminum with iron content, the thickness of intermetallic compound was remarkably increased with increasing iron content. The thickness was shown by following equation in the range of 1-3% iron content; $x=22.5t^{1/2}+4.47{\cdot}t{\cdot}(Fe%)$. where, x is thickness(${\mu}m$), t the time (minute), Fe% the iron w/o. When the Ni-Resist cast iron was dipped into the molten aluminum containing zinc content, the intermetallic compound thickness was also increased with increasing zinc contents. And thickness was represented by the following equation in the range of 2-10% zinc content; $x=3.46t^{1/2}+0.27{\cdot}t{\cdot}(Zn%)$. However, in the case of dipping the Ni-resist cast iron into molten aluminum with silicon content, the thickness of intermetallic compound was decreased with increasing silicon content, as shown in the following equation; $x=7.17t^{1/2}-0.15{\cdot}t{\cdot}(Si%)$. The intermetallic compound formed onto Ni-Resist cast iron was identified to be $FeAl_3\;and\;Fe_3Al$. As the result of hardness measurement, the peak hardness appeared in the intermetallic compound at near interface of the cast iron and the compound.

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Fabrication Process of Laminated Composites by Self-propagating High-temperature Synthesis Reaction (자전고온반응에 의한 적층복합재료의 제조공정)

  • 김희연;정동석;홍순형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2002.05a
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    • pp.155-158
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    • 2002
  • Fabrication process of metal/intermetallic laminated composites by using self-propagating high temperature synthesis(SHS) reactions between Ni and Al elemental metal foils have been investigated. Al foils were sandwiched between Ni foils and heated in a vacuum hot press to the melting point of aluminium. SHS reaction kinetics was thermodynamically analyzed through the final volume fraction of the unreacted Al related with the initial thickness ratio of Ni:Al and diffusion bonding stage before SHS reaction. Thermal aging of laminated composites resulted in the formation of functionally gradient series of intermetallic phases. Microstructure showed that the main phases of intermetallics were NiAl and $Ni_3Al$ having higher strength at room and high temperatures. The volume fractions of intermetallic phases were measured as 82.4, 58.6, 38.4% in 1:1, 2:1, 4:1 initial thickness ratio of Ni:Al.

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A Study of Intermetallic Compound Growth in the Sn/Cu and Sn/Ni Couples (II) : Sheet Resistance and Solderability Changes (Sn/Cu 및 Sn/Ni 계면에서 금속간화합물 형성 및 성장에 관한 연구(II))

  • 김홍석;이성래
    • Journal of the Korean institute of surface engineering
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    • v.22 no.2
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    • pp.47-54
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    • 1989
  • The effects of intermetallic compound growt on the sheet resistance and soldreability as functions of the aging time, the temperature, and the conditions of substrates have been investi-gated in the electroplallic compound (mainy Cu6Sn5and Ni3Sn4) and the number of phase interface increased, the sheet resistance increased. Spread tests showed that the solderability was dereased with the intermetallic compounds growth and increased with the thickness of electroplated Sn. The surface morphology or agin size of the compound layer singificantly affect the solderability. The solderability of Sn/Ni system was superiot to Sn/Ni system was sperior to that of Sn/Cu system and the intermetallic compounds growth was solwer in the former system.

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Ni-Al Based Intermetallics Coating Through SHS using the Heat of Molten Aluminum (알루미늄 주물 위 용탕열을 이용한 N-Al계 금속간화합물의 연소합성 코팅)

  • Lee, Han-Young;Cho, Yong-Jae
    • Journal of Korea Foundry Society
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    • v.31 no.2
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    • pp.83-86
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    • 2011
  • Ni-Al based intermetallic compounds of self-propagating high-temperature synthesis (SHS) by the heat of molten aluminum and been coated on the aluminum casting alloy. The effects of the pouring temperature in casting and the thickness of casting substrate on SHS of the coating layer have been investigated. The experimental result showed that the reaction of the coating layer was activated with increasing the pouring temperature in casting and the thickness of casting substrate. However, the aluminum substrate was re-melted by the heat of formation for intermetallic compounds. Then, it was considered that some mechanical or thermal treatments for elemental powder mixtures were required to control the heat of formation for intermetallic compounds in advance.

CHARACTERIZATION AND ANALYSIS OF SHEAR TEST WITH TESTING CONDITIONS ON BGA PACKAGE

  • Koo, Ja-Myeong;Kim, Dae-Up;Jung, Seung-Boo
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.463-468
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    • 2002
  • This study investigates the variations of shear force, displacement, and fracture surface with the shear speed and the number of reflows. The experimental data of shear tests indicate that the shear force increases as increasing the number of reflows and the shear speed due to the formation of a kind of intermetallic compound, Ni$_3$Sn$_4$, on Au/Ni/Cu pad, and the work-hardening. However, general trends show that the shear force decreases due to increasing the thickness of the intermetallic compound over 4x reflow. It is observed that the intermetallic compound which is formed between solder and pad increases according to increasing the number of reflows, and the growth rate of the intermetallic compound at central region on the interface is faster than one at edge part. The general tendencies of shear force and displacement with different shear speeds are almost identical as an increase of the number of reflows.

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Effects of the Non-equilibrium Heat-treatment on Modification of Microstructures of Al-Si-Cu Cast Alloy (비평형 열처리에 의한 주조용 Al-Si-Cu합금 조직의 개량 효과)

  • Kim, Heon-Joo
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.6
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    • pp.391-397
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    • 2000
  • Addition of Ca element and nonequilibrium heat treatment which promotes shape modification of eutectic Si and ${\beta}$ intermetallic compound were conducted to improve the mechanical properties of Al-Si-Cu alloy. Modification of eutectic Si and dissolution of needle-shape ${\beta}$ intermetallic compounds were possible by nonequilibrium heat treatment in which specimens were held at $505^{\circ}C$ for 2 hours in Al-Si-Cu alloy with Fe. Owing to the decrease in aspect ratio of eutectic Si by the heat treatment of the alloy with 0.33wt.% Fe, the increase in elongation was prominent to be more than double that in the as-cast specimen. Dissolution of needle-shape ${\beta}$ intermetallic compounds in the alloy with 0.85wt.% Fe led to the improvement of tensile strength as the length of ${\beta}$ compounds decreased to 50%.

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The Wetting Property of Indium Solder (인듐 솔더의 젖음특성)

  • 김대곤;이창배;정승부
    • Journal of Welding and Joining
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    • v.20 no.5
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    • pp.106-112
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    • 2002
  • In the present study, the wettability and interfacial tension between (bare Cu, electroless Ni/cu, immersion Au/Ni/Cu) substrates and indium solder were investigated as a function of soldering temperature, types of flux. The wettability of In solder increased with soldering temperature and solid content of flux. The wettability of In solder was affected by the substrate metal finish used, i.e., nickel, gold and copper. On the bare Cu substrate, In solder wet better than any of the substrate metal finishes tested. Intermetallic compound formation between liquid solder and substrate reduced the interfacial energy and improved wettability. For the identification of intermetallic compounds, X-Ray Diffraction(LRD) were employed. Experimental results showed that the intermetallic compounds, such as Cu11In9 and In27Ni10 are observed f3r different substrates respectively. The wetting kinetics is investigated by measuring wetting time with the wetting balance technique. The activation energy of wetting calculated for the In solder/cu substrate and In solder/electroless Au/Ni/Cu substrate are 36.13 and 27.36 kJ/mol, respectively.

Failure analyses of friction welded Al/Cu joints (Al/Cu 마찰용접부의 파단분석)

  • 박재현;권영각;장래웅
    • Journal of Welding and Joining
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    • v.12 no.1
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    • pp.80-93
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    • 1994
  • The microstructure and fractography of the friction welded joint of Al to Cu have been investigated in order to understand the formation of intermetallic compounds and their effects on the failure in tensile test of the joint. The variation of welding pressure did not affect significantly the tensile strength of joint. However, the tensile strength of joint decreaed as welding time increased. The thickness of reaction layers of welded joints was several micro-meters and mainly composed of intermetallic compounds of $CuAl_2$, $Cu_9Al_4$ and Al+$CuAl_2$. The thickness of $CuAl_2$, $Cu_9Al_4$ was increased with welding time. However, $CuAl_2$ was gradually changed to $Cu_9Al_4$ which caused the decrease of tensile strength . Even though the morphology of fractured surfaces depended upon the welding time, the failure occurred along $CuAl_2$ intermetallic compound itself or between $CuAl_2$ and $Cu_9Al_4$ in most cases.

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