• Journal of Welding and Joining
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• v.34 no.3
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• pp.17-22
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• 2016

In terms of mechanical and metallurgical characteristics, the effect of tool plunge depths(0.2, 0.5, 0.7, 1.0, 1.5mm) on weldability in dissimilar Al5083-O/DP590 friction spot joint has been clarified. From the results, it is found that the stirred nugget was stably formed at a plunge depth of more than 0.7mm, which is caused by improved stirring action against each other material. With increasing a plunge depth, the thickness of intermetallic compound(IMC) layer in Al5083-O/DP590 joint has a tendency to increase. The tensile shear strength reaches to the maximum failure load of 6.5kN at a plunge depth of 0.7mm due to relatively small decrease in the thickness of Al5083-O sheet and relatively minute thickness of IMC layer, compared with those of other plunge depth conditions.

• Proceedings of the KWS Conference
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• 2001.10a
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• pp.247-251
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• 2001

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.580-597
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• 2013

Three materials SUS304, 9% Ni steel and Al 5083-O alloy, which are considered possible candidate for International Maritime Organization (IMO) type B Cargo Containment System, were studied. Monotonic tensile, fatigue, fatigue crack growth rate and Crack Tip Opening Displacement tests were carried out at room, intermediate low ($-100^{\circ}C$) and cryogenic ($-163^{\circ}C$) temperatures. The initial yield and tensile strengths of all materials tended to increase with decreasing temperature, whereas the change in elastic modulus was not as remarkable. The largest and smallest improvement ratio of the initial yield strengths due to a temperature reduction were observed in the SUS304 and Al 5083-O alloy, respectively. The fatigue strengths of the three materials increased with decreasing temperature. The largest increase in fatigue strength was observed in the Al 5083-O alloy, whereas the 9% Ni steel sample showed the smallest increase. In the fatigue crack growth rate test, SUS304 and Al 5083-O alloy showed a decrease in the crack propagation rate, due to decrease in temperature, but no visible improvement in da/dN was observed in the case of 9% Ni steel. In the Crack Tip Opening Displacement (CTOD) test, CTOD values were converted to critical crack length for the comparison with different thickness specimens. The critical crack length tended to decrease in the case of SUS304 and increase for the Al 5083-O alloy with decreasing temperature. In case of 9% Ni steel, change of critical crack length was not observed due to temperature decrease. In addition, the changing material properties according to the temperature of the LNG tank were analyzed according to the international code for the construction and equipment of ships carrying liquefied gases in bulk (IGC code) and the rules of classifications.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.75-81
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• 2011

Dissimilar joining of aluminum 6061-T6 alloy to aluminum 5083-O alloy was performed using friction-stir welding technique. The mechanical properties, hardness, macro- and micro-structure on dissimilar friction-stir-weld aluminium alloy were investigated. Mechanical properties of the weld mainly depend on which Al alloy is placed at the retreating sides of the rotating tool respectively during dissimilar friction-stir weld because the microstructure of stir zone was mainly composed of welded Al alloys of the retreating side. Onion ring pattern was observed like lamella structure stacked by each Al alloy in turn. It apparently results in defect-free weld zone that traverse speed was changed to 124 mm/min under conditions of tool rotation speed like 1250 rpm with 5 mm of tool's prove diameter, 4.5 mm of prove length, 20 mm of shoulder diameter, and $2^{\circ}$ of tilting angle. The 231 MPa of ultimate stress and the 121 MPa of yield point are obtained about the friction-stir-welded Al 6061-T6(AS) to Al 5083-O(RS).

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.321-321
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• 2011

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.242-242
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• 2012

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.115-116
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• 2008

• Corrosion Science and Technology
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• v.11 no.5
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• pp.205-212
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• 2012

With recent advances in engineering and technology, a damage on industrial machineries performing high-speed and high-power requirements has become a problem. There is an increasing possibility of cavitation damage, especially in pumps, propellers and high-speed vessels in a flowing liquid accordingly. There are several factors affecting cavitation damage on materials, including viscosity, pressure, temperature, amplitude applied. In this study, effects of cavity pressure in seawater on the damage for 5083-O aluminium alloy were evaluated by modulating amplitude. Trend of the damage with respect to time and amplitude was analyzed comparatively, and surface degradation of specimens was investigated by using Scanning Electron Microscope(SEM) and 3D microscope. The result reveals that the amount of the damage increased consistently with the increase in time and amplitude while the plastic deformation zone where no appreciable damage occurred was in less than 30 minutes.

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.421-429
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• 2018

In this study, various electrochemical experiments were carried out to compare the corrosion characteristics of AA5052-O, AA5083-H321 and AA6061-T6 in seawater. The electrochemical impedance and potentiostatic polarization measurements showed that the corrosion resistance is decreased in the order of AA5052-O, AA5083-H321 and AA6061-T6, with AA5052-O being the highest resistant. This is closely associated with the property of passive film formed on three tested Al alloys. Based on the slope of Mott-Schottky plots of an n-type semiconductor, the density of oxygen vacancies in the passive film formed on the alloys was determined. This revealed that the defect density is increased in the order of AA5052-O, AA5083-H321 and AA6061-T6. Considering these facts, it is implied that the addition of Mg, Si, and Cu to the Al alloys can degrade the passivity, which is characterized by a passive film structure containing more defect sites, contributing to the decrease in corrosion resistance in seawater.

• Journal of Powder Materials
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• v.10 no.1
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• pp.15-20
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• 2003

Hybrid $A1_2O_3-TiC$ ceramic particle reinforced 6061 and 5083 Al composite powders were prepared by the combination of twin rolling and stone mill crushing process, followed by consolidating processes of cold compaction, degassing and hot extrusion. The composite bar consists of lamellar structure of ceramic particle rich area and matrix area, in which the hybrid was decomposed into each TiC of about $3-4\mutextrm{m}$ and $AI_2O_3$ particles of about $1-2\mutextrm{m}$ in diameter. It also found that fine $Mg_2Si$ precipitates of about 30 nm were embedded in the matrix, which have grains of about 3 $\mutextrm{m}$. Higher UTS was measured at the 5083 composite bar compared to the conventionally fabricated composite, due to again refinement effect by the rapid solidification. No particle was shown to form in the interface between the matrix and reinforcement, whereas carbon was diffused into the matrix.