• 한국분말재료학회지
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• 제29권3호
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• pp.233-239
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• 2022

Aluminum alloys are extensively employed in several industries, such as automobile, aerospace, and architecture, owing to their high specific strength and electrical and thermal conductivities. However, to meet the rising industrial demands, aluminum alloys must be designed with both excellent mechanical and thermal properties. Computer-aided alloy design is emerging as a technique for developing novel alloys to overcome these trade-off properties. Thus, the development of a new experimental method for designing alloys with high-throughput confirmation is gaining focus. A new approach that rapidly manufactures aluminum alloys with different compositions is required in the alloy design process. This study proposes a combined approach to rapidly investigate the relationship between the microstructure and properties of aluminum alloys using a direct energy deposition system with a dual-nozzle metal 3D printing process. Two types of aluminum alloy powders (Al-4.99Si-1.05Cu-0.47Mg and Al-7Mg) are employed for the 3D printing-based combined method. Nine types of Al-Si-Cu-Mg alloys are manufactured using the combined method, and the relationship between their microstructures and properties is examined.

• 한국재료학회지
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• 제15권9호
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• pp.598-603
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• 2005

To develope new lead-free solders with the melting temperature close to that of Sn-37Pb$(183^{\circ}C)$, Sn-0.7Cu-5Pb-1Ga, Sn-0.7Cu-5Pb-1Ag, Sn-0.7Cu-5Pb-5Bi-1Ag, and Sn-0.7Cu-SBi-1Ag alloys were composed by adding low-netting elements such as Ga, Bi, Pb, and Ag to Sn-0.7Cu. Then the melting temperatures, microstructures, wettability, and adhesion properties of these alloys were evaluated. DSC analysis showed that the melting temperature of Sn-0.7Cu-SPb-1Ga was $211^{\circ}C$, and those of other alloys was in the range of $192\~200^{\circ}C$. Microstructures of these alloys after heat-treatment at $150^{\circ}C$ for 24 hrs were basically composed of coarsely- grown $\beta-Sn$ grains, and $Cu_6Sn_5$ and $Ag_3Sn$ intermetallic precipitates. Sn-0.7Cu-5Pb-1Ga and Sn-0.7Cu-5Pb-5Bi-1Ag showed excellent wettability, while Sn-0.7Cu-5Bi-1Ag and Sn-0.7Cu-5Pb-5Bi-1Ag revealed good adhesion strength with the Cu substrates. Among 4 alloys, Sn-0.7Cu-5Pb-5Bi-1Ag with the lowest melting temperature $(192^{\circ}C)$ and relatively excellent wettability and adhesion strength was suggested to be the best candidate solder to replace Sn-37Pb.

• 한국진공학회지
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• 제1권1호
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• pp.106-114
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• 1992

여러 조성의 Co-Ni 합금과 Au-Cu 합금에 대하여 XPS와 SIMS 분석방법을 사용하 여 표면분석의 정량화 연구를 수행하였다. XPS의 경우 Co-Ni 합금에 대하여는 수정 없이 고순도 시료만으로 1~2% 상대오차 범위 내에서 정량분석이 가능하였고, Au-Cu 합금의 경 우에는 고순도 시료만을 표준시료로 사용하여서는 정량 분석이 불가능하였고 실험적인 수정 인자를 사용한 경우 1~2% 상대오차로 정량분석이 가능하였다. Au-Cu 합금의 경우 여러 조성이 표준시료가 없는 경우 이론적인 수정인자를 사용하는 경우 10%의 상대오차로 정량 분석이 가능하였다. Co-Ni 합금을 SIMS 분석하였을 때 Co와 Ni의 이차이온 세기의 비가 넓은 농도 범위에서 각 성분의 농도의 비와 직선관계를 가져 SIMS에 의한 합금의 정량분석 이 가능하였다. 또한 VAMAS-SCA Japan Project의 XPS 공동분석의 예비 결과도 주어져 있다.

• 한국주조공학회지
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• 제10권5호
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• pp.426-434
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• 1990

Continuous casting of the Al-Cu-Ni ternary eutectic alloys was carried out by the upward continuous casting process. The morphology of the ternary eutectic growth and the stability of solid-liquid interface were investigated under various growth conditions. It was possible to get the planar solid-liquid interface at the condition of $G_L/R＝3.59{\times}10^3^{\circ}C\;sec/mm^2$ in Al-Cu-Ni ternary eutectic alloys. In Al-rich, Ni-rich and Cu-rich hypereutectics of Al-Cu-Ni ternary alloys, primary ${\alpha},\;{\tau}\;and\;{\theta}$ dendrites have grown as the leading phase ahead of the ternary eutectic composites.

• 열처리공학회지
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• 제16권5호
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• pp.267-274
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• 2003

The effect of the thermo-mechanical treatment on the microstructural development and the electric conductivity of Cu-Ca alloys are studied for the thixoforming processed rotor of the induction motor The Cu-Ca alloys containing Ca less than 1.0wt% show the electrical conductivity higher than 80% IACS They also show broad melting range over $150^{\circ}C$ which is desirable for the thixoforming process The semi-solid microstructure of cast alloy changes from the dendrite structure to globular structure by prior deformation before reheating. The details of microstructural changes by the thermo-mechanical treatment are discussed.

• Journal of Magnetics
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• 제15권1호
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• pp.32-35
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• 2010

The effects of Cu-addition and die-upset temperature on the texture in the die-upset Nd-lean $Nd_xFe_{93.5-(x+y)}-Cu_yGa_{0.5}B_6$ (x = 9-12, y = 0-2) alloys were investigated. The die-upset Cu-containing Nd-lean $Nd_{12}Fe_{81.5-y}-Cu_yGa_{0.5}B_6$ (y = 1, 2) alloys showed a considerable texture. Texture in the Nd-lean alloys developed through basal plane slip deformation. The Cu-addition reduced the melting point of grain boundary phase facilitating grain gliding during the die-upsetting, and providing a greater chance for the $Nd_2Fe_{14}B$ grains to meet the deformation conditions. Die-upsetting at higher temperature facilitated grain gliding and plastic deformation, thus enhancing texture.

• Journal of Welding and Joining
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• 제23권6호
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• pp.93-98
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• 2005

The purpose of this study is to investigate the characteristics of pb-free $Zn-(3\~6)\%Al-(1\~6)\%Cu$ solder alloys for ultra high temperature(>573K) which applied to air craft, space satellite, automotive, oil, gas well exploration and data logging of geo-thermal wells. Melting range, solderability, electric resistivity, microstructure and mechanical properties were examined with solder alloys casted in Ar gas atmosphere. $Zn-4\%Al-(1\~3)\%Cu,\;Zn-5\%Al-(2\~4)\%Cu\;and\;Zn-6\%Al-(3\~5)\%Cu$ alloys satisfied the optimum melting range of 643 to 673k for ultra high temperature solder. A melting temperature increased with increasing Cu content, but decreased with increasing Al content. The spreadability was improved with increasing hi content. But the content of Cu had no effect on the spreadability. The electric resistivity was lowered with increasing Al and decreasing Cu content. In all Zn-Al-Cu solder alloys, primary dendritic $\varepsilon$ phase(Zn-Cu), dendritic $\eta$ phase(Zn-Cu-Al), $\alpha(Al-Zn)-\eta$ eutectic and eutectoid phase were observed. The addition of Al increased the volume fraction of eutectic and eutectoid phase and it decreased f phases. Also, the addition of Cu increased slightly the volume fraction of e, the eutectic and eutectoid phases. With increasing total content of Al and Cu, a hardness and a tensile strength were linearly increased, but anelongation was linearly decreased.

• 한국주조공학회지
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• 제34권4호
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• pp.130-135
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• 2014

Efforts have been made to develop new silicon-free aluminum casting alloys that possess high electrical and thermal conductivity. In this research Al-Fe-Cu-Mg alloys with various Cu and Mg contents were investigated for their various properties. As the Cu or Mg content was increased, the electrical conductivity gradually decreased, while the tensile strength of the Al-Fe-Cu-Mg alloy tended to be improved. It was found that fluidity was generally inversely proportional to the Cu content, but the alloys containing 1%Mg showed considerably low fluidity, regardless of the Cu content.

• 방사성폐기물학회지
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• 제21권1호
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• pp.1-8
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• 2023

The major concern in the deep geological disposal of spent nuclear fuels include sulfide-induced corrosion and stress corrosion cracking of copper canisters. Sulfur diffusion into copper canisters may induce copper embrittlement by causing Cu₂S particle formation along grain boundaries; these sulfide particles can act as crack initiation sites and eventually cause embrittlement. To prevent the formation of Cu₂S along grain boundaries and sulfur-induced copper embrittlement, copper alloys are designed in this study. Alloying elements that can act as chemical anchors to suppress sulfur diffusion and the formation of Cu₂S along grain boundaries are investigated based on the understanding of the microscopic mechanism of sulfur diffusion and Cu₂S precipitation along grain boundaries. Copper alloy ingots are experimentally manufactured to validate the alloying elements. Microstructural analysis using scanning electron microscopy with energy dispersive spectroscopy demonstrates that Cu₂S particles are not formed at grain boundaries but randomly distributed within grains in all the vacuum arc-melted Cu alloys (Cu-Si, Cu-Ag, and Cu-Zr). Further studies will be conducted to evaluate the mechanical and corrosion properties of the developed Cu alloys.

• 한국주조공학회지
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• 제30권6호
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• pp.205-209
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• 2010

This study evaluates the influence of strontium addition and holding time on mechanical properties for Al-10.5wt%Si-2wt%Cu secondary die-casting alloy and the measured electrical conductivity of modified alloys. A general improvement in the mechanical properties of the alloy was observed after adding the strontium. Ultimate tensile strength, elongation and electrical conductivity of modified alloys were improved by increasing strontium content and holding time. From these results, the optimal strontium content and holding time were identified on the mechanical properties of Al-10.5wt%Si-2wt%Cu secondary die-casting alloys.