• E2M - 전기 전자와 첨단 소재
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• 제10권10호
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• pp.995-999
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• 1997

For melt-spun Fe-Nd-C alloy variation of phase development and magnetic properties with the variety of small Al addition was investigated. As the amount of Al addition increased the amorphization of Fe$_{14}$/Nd$_{2}$/C or $\alpha$-Fe was retarded and the residual Fe$_{14}$/Nd$_{2}$/C or $\alpha$-Fe did not eliminated after heat treatment resulting in poor coercivities of the ribbons. The grain size of Fe$_{14}$/Nd$_{2}$/C increased with the increase of Al addition and the abnormal grain was often found out in the ribbon heat treated for more then 10 min. The enhancement of coercivity was the highest with the addition of 0.5at%Al. As the amount of Al addition increase the coercivities dropped rapidly. The highest coercivity obtained so far is 13.9kOe which about 16% higher than that(11.2kOe) obtained from the Al-free specimen.

• 한국주조공학회지
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• 제24권6호
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• pp.356-365
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• 2004

Mechanical properties and microstructures of the Ni-AI-Fe and Ni-AI-Fe-(B, Zr) alloys which containing $10{\sim}30at$.%Fe, 0.1at.%B and/or 0.1at.%Zr have been investigated. The experimental results showed that the microstructures of Ni25Al were changed from a single phase ${\gamma}$ to dual phase ${\gamma}$ and ${\beta}$ by addition of 27at.%Fe. Ni45Al, however, kept the single ${\beta}$ phase even though Fe was added upto 30at.%. The hardness of Ni25Al were increased from $H_RB$ 70 to $H_RC$ 39 by addition of 27at.%Fe. In the case of Ni45Al which have $H_RC$ 37, the hardness was decreased by lOat.%Fe addition, but increased with 30at.%Fe. The yield strength and ultimate compressive strength in the compressive test have showed a similar trend with the hardness change. The strain to fracture was 14% at maximum and achieved in Ni25Al-27at.%Fe and Ni25Al-27at.%Fe-0.1 at.%B alloys. The Ni45Al showed a relatively low strain to fracture as 4%. The impact absorption energy of Ni25Al increased from 0.74 kg-m to 1.81 kg-m by addition of 27at.%Fe. In case of Ni45Al, the addition of lOat.%Fe and lOat.%Fe with small amounts of Band Zr did not change significantly the impact absorption energy of 0.60 kg-m, whereas the addition of 30at.%Fe with small amounts of B and Zr increased it slightly. In fracture tests, both of two basic materials showed the same intergranular fracture but by adding Fe it changed to the cleavage fracture mode or co-existing of cleavage and intergranular fractures.

• 동력기계공학회지
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• 제10권2호
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• pp.83-88
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• 2006

Corrosion characterization of Fe-XAl-0.3Y(X=5, 10, 14 wt%) alloys in $0.1{\sim}1N$ sulphuric acid at room temperature was studied using potentiodynamic techniques. The morphology and components of corrosion products on surface of Fe-aluminide alloys were investigated using SEM/EDX, XRD. The potentiodynamic polarization curve of alloys exhibited typical active, passive, transpassive behaviour. Corrosion potential($E_{corr}$) and corrosion current density($I_{corr}$) values of Fe-XAl-0.3Y alloys followed linear rate law. $E_{corr}$ of 10Al alloy and 14Al alloy was ten times lower than 5Al alloy. Icorr of 14Al alloy was five times lower than 5Al alloy. The passive film on the surface of Fe-5Al-0.3Y alloy was formed iron oxide. Fe-10Al-0.3Y and Fe-14Al-0.3Y alloys passive films were aluminium oxide. especially, Fe-14Al-0.3Y alloy showed good corrosion resistance in $0.1{\sim}1N$ sulphuric acid. This is attributed to the forming of protective $Al_2O_3$ oxide on the surface of Fe-14Al-0.3Y alloy.

• 한국표면공학회지
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• 제36권6호
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• pp.444-454
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• 2003

The effect of trace metallic additives of Al-Fe-X on microstructure, glossiness and hardness of Zn electrodeposits was investigated by using sulfate bath. The preferred orientation of Zn deposits with Al-Fe additives was (10 l)(l:3,4,2), while that of Zn deposits with Al-Fe-X(Ni,Co) additives was either (002) or (002)＋(103)ㆍ(104) mixed orientation. The preferred orientation of Zn deposits with Al-Fe-Cr additives changed from (002)+(10 l) to (10 l) orientation with increasing amount of Al additive. The surface morphology of the Zn deposits was closely related to the preferred orientation of the deposits. The glossiness of Zn deposits with Al-Fe additives increased in comparison with that of pure Zn deposit. That of the Zn deposits with Al-Fe-X additives was related to the morphology of the deposits and changed according to type of additives. The hardness of Zn deposits with Al-Fe-X(Ni,Co,Cr) additives was noticeably higher than that of Zn deposits with Al-Fe additives.

• 한국표면공학회지
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• 제37권2호
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• pp.128-136
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• 2004

Effects of alloying elements on the surface characteristics of Fe-38Al intermetallic compounds were investigated using potentiostat. The specimens were casted by the vacuum arc melting. The subsequent homogenization and the stabilization led to the homogeneous DO$_3$ structure of the specimen. After the corrosion tests, the surface of the tested specimen was observed by the optical microscopy and scanning electron microscopy(SEM). For Fe-38 at.% Al intermetallic compound, the addition of Cr and Mo proved to be beneficial in decreasing the grain boundary attack by decreasing the active current density. Addition of Band Nb resulted in a higher active current density and also a higher passive current density. These results indicated the role of Cr and Mo in improving the pitting corrosion resistance of Fe-38 at.%Al intermetallic compound. Band Nb addition to Fe-38 at.%Al accelerated the granular corrosion. Fe-38 at.%Al containing Cr and Mo showed remarkably improved pitting corrosion resistance in comparison with Band Nb addition to Fe-38 at. %Al.

• 한국결정성장학회지
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• 제19권4호
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• pp.202-207
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• 2009

본 연구에서는 $Fe/Al_2O_3$ 및 $Fe/TiO_2$계 나노복합분말을 제조하기 위하여 실온 기계적 합금화법(MA)을 적용하였다. $Fe_3O_4-M$(M= AI, Ti)이고 여기서 순금속 Al 및 Ti은 고상반응 시 환원제로서 선택하였다. $Fe_3O_4$-순금속의 각각 25시간 및 75시간 MA 처리한 결과 $Fe/Al_2O_3$ 및 $Fe/TiO_2$ 나노복합분발이 얻어졌으며, 이것은 나노결정립의 ${\alpha}$-Fe 기지에 $Al_2O_3$ 및 $TiO_2$가 각각 미세하게 분산된 나노복합분말임을 알 수 있었다. 또한 Fe$_3$O$_4$-AI계에서 보다 짧은 반응 시간에 복합분말이 생성되는 것은 $Fe_3O_4$의 Al에 의한 환원반응 시 큰 반응열에 기인하는 것으로 사료된다. MA법으로 제조된 $Fe/TiO_2$ 복합분말의 X선 회절분석으로부터 ${\alpha}$-Fe 결정립 크기는 30 nm 임을 알 수 있었다. 또한 MA 과정 중 시료의 자기 측정으로부터 $Fe_3O_4$의 순금속 Al 및 Ti 에 의한 고상환원반응 과정을 자세히 관찰할 수 있었다.

• 한국자기학회지
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• 제8권4호
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• pp.198-202
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• 1998

AlxFe3-xO4를 직접합성법으로 제조하여 x-선 회절법과 Mossbauerqnsrhkd법으로 연구하였다. Mossbauer spectrum에서 subspectrum 흡수면적비에 의하여 이온분포를 졀정하였다. 팔면체자리(B-site)에 들어 있는 Fednjs자는 Aldnjs자의 첨가량과 관계없이 hopping Fe2+ (Fe3+,Al3+)에 의한 Fe2.5+의 전하상태에 있다.

• 한국재료학회지
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• 제33권9호
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• pp.353-359
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• 2023

This study investigated the growth behavior and characteristics of compounds formed at the interface between a liquid Al-Si-Cu alloy and solid cast iron. Through microstructural analyses, it was observed that various AlFe and AlFeSi phases are formed at the interface, and the relative proportion of each phase changes when small amounts of strontium are added to the Al alloy. The results of the microstructural analysis indicate that the primary phases of the interfacial compounds in the Al-Si-Cu base alloy are Al₈Fe₂Si and Al_4.5FeSi. However, in the Sr-added alloys, significant amounts of binary AlFe intermetallic compounds such as Al₅Fe₂ and Al₁₃Fe₄ formed, in addition to the AlFeSi phases. The inclusion of Sr has a slight diminishing effect on the rate at which the interfacial compounds layer thickens during the time the liquid Al alloy is in contact with the cast iron. The study also discusses the nano-indentation hardness and micro-hardness of the interfacial phases.

• 대한금속재료학회지
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• 제50권6호
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• pp.455-462
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• 2012

Al-Si coated boron steel and Zn coated DP steel plates were laser-welded to manufacture a Tailor Welded Blank (TWB) for a car body frame. Hot-stamping heat treatment ($900^{\circ}C$, 5 min) was applied to the TWB weld, and the microstructural change and transformation mechanism were investigated in the Al-rich area near the bond line of the Al-Si coated steel side. There was Al-rich area with a single phase, $Fe_3(Al,Si)$, which was transformed to ${\alpha}-Fe$ (Ferrite) after the heat treatment. It could be explained that the $Fe_3(Al,Si)$ phase was transformed to ${\alpha}-Fe$ during heat treatment at $900^{\circ}C$ for 5 min and the resultant ${\alpha}-Fe$ phase was not transformed by rapid cooling. Before the heat treatment, the microstructures around the $Fe_3(Al,Si)$ phase consisted of martensite, bainite and ${\alpha}-Fe$ while they were transformed to martensite and ${\delta}-Fe$ after the heat treatment. Due to the heat treatment, Al was diffused to the $Fe_3(Al,Si)$ and this resulted in an increase of Al content to 0.7 wt% around the Al-rich area. If the weld was held at $900^{\circ}C$ for 5 min it was transformed to a mixture of austenite (${\gamma}$) and ${\delta}-Fe$, and only ${\gamma}$ was transformed to the martensite by water cooling while the ${\delta}-Fe$ was remained unchanged.

• 한국자기학회지
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• 제3권2호
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• pp.135-138
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• 1993

Fe-B계 비정질합금에 Al을 치환한 $Fe_{82}B_{18-x}Al_{x}$ 및 $Fe_{80}B_{20-x}Al_{x}$급속응고합금의 포화자왜 인장응력에 의한 자기탄성효과가 조사되었다. 포화자왜는 Al 치환량이 증가 할수록 증가 하며, 비정질 $Fe_{82}B_{14}Al_{14}$합금에서 45 ppm으로 가장 높다. 비정질 $Fe_{82}B_{14}Al_{14}$ 합금의 인장응력에 따른 최대자속밀도의 변화율은 약 $0.026\;T.mm^{2}/N$으로 고분해능 역학센서로 응용이 가능할 것으로 예상된다.