• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1875-1881
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• 2016

The wear behavior for the two types of composites, those are epoxy matrix composites filled with silica particles and aluminium matrix composites filled with SiC particles, were compared to investigate the wear mechanism for these composites. Especially, the effect of the volume fraction for the epoxy matrix composites and the particle size for the aluminium matrix composites according to the apply load and sliding velocity were investigated. Wear tests of the pin-on-disc mode were carried out and followed by scanning electron microscope observations for the worn surface. The addition of the fillers in the composites were improved the wear resistance significantly and changed the wear mechanism for the both composites. These results were identified by the observation of the worn surface after testing.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.73-79
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• 2002

Fretting wear test in room temperature air was performed to evaluate the wear mechanism of fuel rod using a fretting wear tester, which has been developed for experimental study. The main focus was to compare the wear behaviors of fuel rod against support springs at different contact geometries (i.e. concave and convex) and slip directions (axial and transverse). The wear on the tube was examined by the surface roughness tester, which measures the volume. The result indicated that with change of contact geometry from 5N of normal load to 0.1mm gap, wear volume of tube Increased in the condition of concave spring, but slowly decreased in convex spring. From the results of SEM observation, wear mechanism of each test condition was also depend on the above contact parameters. The wear mechanism of each test condition in room temperature air is discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1619-1629
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• 1995

The Al/Al$_{2}$O$_{3}$ SiC and Al/Al$_{2}$O$_{3}$/C hybrid metal matrix composites (MMCs) were fabricated by squeeze infiltration method. Uniform distribution of reinforcements were found in the microstructure of metal matrix composites. Mechanical tests were carried out under various test conditions to clearly identify mechanical behavior of MMCs, and the wear mechanism of Al/Al$_{2}$O$_{3}$/(SiC or C) hybrid metal matrix composites were investigated. The tensile strength and hardness of hybrid composites was resulted in increasing compared with those of the unreinforced matrix alloy. Wear resistance was strongly dependent upon kinds of fiber, volume fraction and sliding speed. The wear resistance of metal matrix composites was remarkably improved by the addition of reinforcements. Especially, the wear resistance of the hybrid composites of carbon fibers was more effective than in the composites reinforced with alumina and SiC whiskers of reinforcements. This was due to the effect of carbon fiber on the solid lubrication. Wear mechanisms of hybrid composites were suggested from wear surface analyses. The major wear mechanism of hybrid composites was the abrasive wear at low to intermediate sliding speed, and the melting wear at intermediate to high sliding speed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.105-108
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• 2005

Sliding wear mechanism of a high nitrogen austenitic 18Cr-18Mn-2Mo-0.9N steel has been investigated. Dry sliding wear tests of the steel were carried out at various loads of 1N-10N under a constant sliding speed condition of 0.15m/s against AISI 52100 bearing steel balls. Solution $(1050^{\circ}C)$ and isothermal aging $(900^{\circ}C)$ heat treatments were performed on the steel and the effect of the heat treatments on the wear were investigated. Wear rates of the solution-treated steel specimen remained low until 5N, and then increased abruptly at loads above 5N. The rates of isothermally aged specimens were low and increased gradually with the applied load. Worn surfaces, their cross sections, and wear debris of the steel specimens were examined with a scanning electron microscopy. Phases of the heat-treated specimen and the wear debris were identified using XRD. Phases transformed underneath the sliding track during the wear were investigated and analyzed using TEM. Effects of the phase transformation during the wear and $Cr_2N$ precipitates formed during the isothermal aging on the wear of the austenitic steel were discussed.

• Transactions of Materials Processing
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• v.15 no.2 s.83
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• pp.112-117
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• 2006

Sliding wear mechanism of a high nitrogen austenitic 18Cr-18Mn-2Mo-0.9N steel has been investigated. Dry sliding wear tests of the steel were carried out at various loads of IN-10N under a constant sliding speed condition of 0.15m/s against AISI 52100 bearing steel balls. Solution ($1050^{\circ}C$) and isothermal aging ($900^{\circ}C$) heat treatments were performed on the steel and the effect of the heat treatments on the wear was investigated. Wear rates of the solution-treated steel specimen remained low until 5N load, and then increased abruptly at loads above 5N. The rates of isothermally aged specimens were low and increased gradually with the applied load. Worn surfaces, their cross sections, and wear debris of the steel specimens were examined with a scanning electron microscopy. Phases of the heat-treated specimen and the wear debris were identified using XRD. The transformed phase underneath a sliding track was investigated and analyzed using a TEM. Effects of the phase transformation during the wear and $Cr_{2}N$ precipitates formed during the isothermal aging on the wear of the austenitic steel were discussed.

• Tribology and Lubricants
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• v.16 no.1
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• pp.33-38
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• 2000

Abstract- In this paper tribological characteristics of solid and liquid phase sintered W/C-35%Ni tappets were investigated. Three test methods were performed to investigate the wear and surface damage mechanism of sintered tappets. First, block-on-ring wear test was performed to investigate the wear characteristics under pure sliding condition. Second, simplified cam and tappet tests (called component wear test hereafter) were carried out to simulate the real contact history of cam and tappet. Also, after the test, contact surfaces were analyzed with scanning electron microscope to study the wear mechanism. As a final screening, engine dynamo tests were performed. Results showed that in the block on ring sliding wear test, solid phase sintered specimens showed superior wear resistance to liquid phase sintered specimens. The component wear tests and engine dynamo tests also showed the same results. Therefore, in these tests, solid phase sintered tappet material revealed superior wear resistant properties to liquid phase sintered one.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.80-88
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• 1997

Repeated sliding contact wear test was performed with copper specimens to obtain the relationship between wear and surface hardening. Wear surface and wear track section were observed by optical microscopy. Wear volume and micro-vikers hardness of sublayer below wear surface were obtained. These results suggested that wear mechanism depended on contact load than sliding velocity. Therefore wear mechanism was abrasive wear within critical contact load and adhesive wear over critical contact load. Wear rate increased with contact load, sliding distance but decreased with sliding velocity. Surface hardening increased with sliding velocity and sliding distance but decreased with contact load.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.421-424
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• 2007

Dry sliding wear behavior of ultra-fine grained (UFG) plain low carbon dual phase steel, of which microstructure consists of hard martensite in a ductile ferrite matrix, has been investigated. The wear characteristics of the UFG dual phase steel was compared with that of a coarse grained dual phase steel under various applied load conditions. Dry sliding wear test were carried out using a pin-on-disk type tester at various loads of 1N to 100N under a constant sliding speed condition of 0.20m/s against an AISI 52100 bearing steel ball at room temperature. The sliding distance was fixed as 1000m for all wear tests. The wear rate was calculated by dividing the weight loss, measured to the accuracy of 10-5g by the specific gravity and sliding distance. The worn surfaces and wear debris were analyzed by SEM, EDS and profilometer. Micro-vickers hardness of the cross section of worn surfaces were conducted to analyze strain hardening underneath the contact surfaces. The wear mechanism of the UFG dual phase steel was investigated with emphasis on the unstable nature of the grain boundaries of the UFG microstructure.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.299-303
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• 2007

Dry sliding wear behavior of ultra-fine grained(UFG) plain low carbon dual phase steel, of which microstructure consists of hard martensite in a ductile ferrite matrix, has been investigated. The wear characteristics of the UFG dual phase steel was compared with that of a coarse grained dual phase steel under various applied load conditions. Dry sliding wear test were carried out using a pin-on-disk type tester at various loads of 1N to 100N under a constant sliding speed condition of 0.20m/s against an AISI 52100 bearing steel ball at room temperature. The sliding distance was fixed as 1000m for all wear tests. The wear rate was calculated by dividing the weight loss, measured to the accuracy of 10-5g by the specific gravity and sliding distance. The worn surfaces and wear debris were analyzed by SEM, EDS and profilometer. Micro-vickers hardness of the cross section of worn surfaces were conducted to analyze strain hardening underneath the contact surfaces. The wear mechanism of the UFG dual phase steel was investigated with emphasis on the unstable nature of the grain boundaries of the UFG microstructure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.124-130
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• 1998

The wear characteristics and wear mechanisms of dental composite resins were investigated. Composite resins such as Metalii, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to analyze the effect of Prepolymerized Particle Fillers in friction and wear characteristics. Ball on flat wear tester was used for a wear test. Friction and wear tests are carried out at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistance of Silux Plus and Palfique Estelite was better than that of Metafil and Hellomolar at the same experimental condition. The main wear mechanism is plastic flow and abrasive wear by crack propagation.