• 한국재료학회지
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• 제34권7호
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• pp.330-340
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• 2024

Al-Mg-Si alloys are light weight and have excellent corrosion resistance, and are attracting attention as a liner material for high-pressure hydrogen containers in hydrogen fuel cell vehicles. Because it has excellent plastic hardening properties, it is also applied to car body panel materials, but it is moderate in strength, so research to improve the strength by adding Si-rich or Cu is in progress. So far, the authors have conducted research on the intergranular fracture of alloys with excessive Si addition from the macroscopic mechanical point of view, such as specimen shape. To evaluate their impact tensile properties, the split-Hopkinson bar impact test was performed using thin plate specimens of coarse and fine grain alloys of Al-Mg-X (X = Cr,Si) alloy. The effect of the shape of the specimen on the characteristics was studied through finite element method (FEM) analysis. As a result, it was found that the intergranular fracture of the alloy with excessive Si depended on the specimen width (W)/grain size (d), which can be expressed by the specimen size and grain size. As W/d decreases, the intergranular fracture transforms into a transgranular fracture. As the strain rate increases, the fracture elongation decreases, and the fracture surface of the intergranular fracture becomes more brittle. It was confirmed that intergranular fracture occurred in the high strain rate region even in materials with small grain sizes.

• 한국분말재료학회지
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• 제1권1호
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• pp.66-71
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• 1994

Optical microstructures and mechanical properties of Na gas atomized Al-20Si-5Fe alloying powder and its hot extrudates were studied on 3 different types of powder size distribution. This powder showed the size distribution of 10~210 $\mu\textrm{m}$. Also the microstructures of $\alpha$-Al, primary and eutectic Si and needle shaped intermetallic compounds were observed by optical microscope. These needle shaped intermetallic compounds were identified as ${\delta}Al_4FeSi_2$- by XRD and EDX analysis. The ultimate tensile strength(UTS) of these alloy extrudates was increased from 324 to 390 MPa with decreasing powder size range from 120~210 $\mu\textrm{m}$ to 10~64 $\mu\textrm{m}$. A value of Micro-vic-kers hardness was simillar to the result of UTS. These extrudates showed better wear resistance than those of Al-20Si-2X(X : Ni, Cr, Zr), although they are insensitive to the size distribution. These results indicate that the presentation of ${\delta}Al_4FeSi_2$ intermetallic compounds contributed to the wear resistance improvement.

• 대한금속재료학회지
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• 제49권3호
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• pp.231-236
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• 2011

Nanopowder of $Fe_2O_3$, Al, Cr and Si was fabricated by high energy ball milling. A dense nanostuctured $A_2O_3$ and $6.06Fe_{0.33}Cr_{0.16}Al_{0.23}Si_{0.29}$ composite was simultaneously synthesized and consolidated using high frequency induction heated sintering method within 1 minute from mechanically activated powders of $Fe_2O_3$, Al, Cr and Si. The grain sizes of $Al_2O_3$ and $Fe_{0.33}Cr_{0.16}Al_{0.23}Si_{0.29}$ in composite are 80 and 18 nm, respectively.

• 한국표면공학회지
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• 제32권2호
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• pp.100-108
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• 1999

The microstructure and corrosion properties of Al-Si diffusion coated PWA1426 alloy have been investigated. Experimental variables are included temperatures of heat-treatment and coating thickness. The microstructure of coated layer and corrosion properties were analysed by SEM, EDS and hot corrosion test. Two major processes have been found to contribute to microstructural changes in the coating. These are, firstly, the transformation of the NiAl to other $Ni_2Al_3$-based phase and secondly, the precipitation of Cr containing phases. Specimens heat treated at $1080^{\circ}C$ showed superior corrosion resistance to heat treated at $880^{\circ}C$. These increase in life was attributed to the transformation of NiAl and increased coating thickness of PWA1426 alloy.

• 대한치과보철학회지
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• 제30권4호
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• pp.481-492
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• 1992

Author measured the bonding strength between Dental Porcelain and Nonprecious Dental Alloy and analyzed diffusion Phenomena at the interfaceby by Auger electron spectroscopy and also Electron spectroscopy for Chemical Analysis. The each specimen was sputtered with Al, Cr, In and Sn. 1. Ni whic is the main element of the matris of dental nonprecious alloy diffuse more than the other element and the Ni diffusion rate of each specimen was well coordinated with the bonding strength of each. 2. The Sn thin film suppress the diffusion rate of Ni of matrix into the Dental Porcelain than the In or Cr thin films. 3. The Al thin film suppress the diffusion rate of Ni than the Sn thin film. 4. The main coponent of dental porcelain : Al, Si, Mo diffused into the matrix of alloy. It means that the each element of dental alloy and dental porelain diffused into the each other part.

• 한국표면공학회지
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• 제30권4호
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• pp.248-254
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• 1997

The sulfidation behavior of a sputter-deposited amorphous coating of 69.0%Nb-16.9Ni-11.9%Al-2.2%Si (at.%) has been investigated as a funtion of temperature.(973-1173K) in pure sulfur pressure of 0.01atm. The sulfidation kinetics of the casting obyed the parabolic rate low over the whole temperature ranges studied. The stlfidation rate increased with the temperature, as expected. The sulfide scale, the composition of which was $Al_2S_3,\;NbS_2,\;Ni_{3-x}S_2\;and\;FeCrS_4$, formed on the amorphous coating was primarily bilayered. Both the outer fastgrowing non-protective 4Al_2S_3$scale and the inner slowly-growing protective $NbS_2$,/TEX> scale and the inner slowly-growing protective $NbS_2$ scale had some Fe and Cr dissolution, which evidently came from the base substrate alloy of stainless steel type 304. Belows the coating, Kirkendall void formation was noticed. Nevertheless, a dramatic improvement of sulfidation resistance was achieved by sputter-depositing Nb-2 Ni-Al-Si layer on the stainless steel 304.

• Corrosion Science and Technology
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• 제18권3호
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• pp.73-77
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• 2019

Hot-dip aluminized coating has been widely used to protect steel substrate against corrosion. In this study, the corrosion behavior of hot-dip aluminized type 409L (11% Cr) stainless steel (SS) was investigated using macro- and micro-scale polarization tests. An Al-Fe-Si alloy layer that was formed due to inter-diffusion of alloying elements between Al coating and SS substrate was observed between Al coating and 409L SS substrate. In both macro- and micro-scale polarization tests, the corrosion potential ($E_{corr}$) of the 409L SS substrate was much nobler than that of the Al coating and alloy layer. $E_{corr}$ of the alloy layer was between that of Al coating and 409L SS substrate. This indicates that the alloy layer can act as a buffer between the more active Al coating and the nobler SS substrate for pit growth in aluminized SS. The presence of the alloy layer appears to be helpful in hindering pitting corrosion of aluminized SS.

• 연구논문집
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• 통권27호
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• pp.201-208
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• 1997

본 연구에서는 배기 가스 촉매정화용 금속담체 지지체의 접합특성을 향상시키기 위하여, 브레이징 접합부의 고온내산화성에 미치는 브레이징 합금원소의 영향을 고찰하였다. 브레이징은 Ni계 합금인 BNi-5 분말(Ni-Cr-Si계합금)과 MBF-50 foil(Ni-Cr-Si-B계 합금)을 사용하여 $1200^\circC$의 진공중에서 행하였다. 약 1-1.5 wt%의 B을 함유한 MBF-50으로 브레이징된 시편이 BNi-5로 브레이징된 시편에 비해 내산화성이 떨어지는 것으로 나타났으며. 이것은 합금/브레이징 계변을 따라 형성된 Kirkendall void를 통한 산소의 빠른 침투로 인한 것으로 생각된다.

• 대한치과기공학회지
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• 제28권2호
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• pp.321-329
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• 2006

The popularity of Ni-Cr-Mo based metal alloys for metal-ceramic crown have increased recently because of low price, superior yield strength and rigidity. the use of these alloys give them the potential advantage of thinner copping with the required rigidity for long span bridges. The purpose of this study was to assess the microstructures and mechanical properties of Ni-Cr-Mo-(Si,Al,Nb,Zr,Ti.Cu,Mm) based Alloys not containing beryllium(Be) related toxic effects. The abtained results indicated that as-cast these specimen alloys showed compositional and microstructural differences, and mechanical properties values of Ni69Cr20Mo5Si2Al4 alloy among these specimen alloys was found to be superior to those of commercial Ni-Cr based alloy using in market place today.

• Journal of Welding and Joining
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• 제18권3호
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• pp.51-59
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• 2000

Sink roll has been used in molten 55%Al-Zn alloy bath of continuous galvanizing line for sinking and stabilizing working steel strip in molten metal bath. In the process, the sink roll body inevitably build up dross compounds and pitting on the sink roll surface during 55%Al-Zn alloy coated strip production, and the life time of the sink roll is shorten by build up dross compounds and pitting. The present study examined the application of thermally sprayed ceramic coatings method on sink roll body for improving erosion resistance at molten 55% Al-Zn pool. In this experiment, the stainless steels such as STS 316L and STS 430F were used as the substrate materials. The CoNiCr and WE-Co powder were selected as bond coating materials. Moreover $Al_2O_3-ZrO_2-SiO_2 and ZrO_2-SiO_2$ powders selected as the top coating materials. Appearances of the specimens before and after dipping to molten 55%Al-Zn pool were compared and analyzed. As a result of this study, STS430F of substrate, WC-Co of bond spray coatings, $ZrO_2-SiO_2$ power of top spray coatings is the best quality in erosion resistance test at molten 55%Al-Zn pool