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A hydrogenated carbon film was prepared in our laboratory and the analysis of high-resolution transmission electron microscopy (HRTEM) shows that the film consists of high curvature fullerene-like rings and fingerprint structures interspersing in amorphous carbon matrix. Friction behaviors of the film sliding against Si 3 N 4 ball were investigated on a ball-on-disk tester in different...
ZrO 2 -based composites containing electro-conductive secondary phases have successfully proven their feasibility for electrical discharge machining (EDM) in demineralised water. Samples of ZrO 2 –TiN composites with 40vol.% TiN were self-developed and manufactured by wire-EDM. The effect of the surface finishing condition on the tribological characteristics was investigated by comparing...
Brake noise is an example of noise caused by vibrations induced by friction forces. During brake operation, the friction between the pad and the disc can induce a dynamic instability in the system. Brake squeal can occur in the frequency range between 1 and 20kHz, and more. Approaches to this problem are usually confined to the analysis of the system dynamics or to the tribological studies (analysis...
A new rapid method of nano-scale wear testing was applied to a matrix of 150nm amorphous C and Cr doped amorphous C coatings in order to investigate a nano-wear process under conditions which are applicable to MEMS and similar devices. The nano-wear test involved adding a method of controlled oscillation to the sample mounting of a nanoindentation system utilising a spherical ruby counter-body. At...
The Research Committee on Cavitation Erosion in the Turbomachinery Society of Japan has already reported the prediction method of cavitation erosion rate. However, the scattering between the predicted rate and the measured rate is 100 times. In this study, we compare fundamental data of stainless steels collected by the Committee with the data obtained in our laboratory. The influence of material...
This paper presents results from simulations of railhead wear due to initial sinusoidal and broad-band roughness using a time-domain wheel–track vertical interaction model integrated with a three-dimensional wheel–rail contact model. As typical roughness wavelengths are short and frequencies are high compared with vehicle body motions, the vehicle is simplified to an unsprung wheel mass. The rail...
In this study, extrusion die wear during the metal matrix composite (MMC) extrusion process was investigated with regard to the size of the reinforcement particle. Extrusion die materials were AISI H13 hot working die steel and were machined by EDM in order to gain rectangular and circular die bearings. The dies were hardened, tempered and grounded to be prepared for extrusion processes.AA 6063 aluminium...
Since the loss of properties of organic coatings due to abrasion is of primary importance in the material performance, the reduction of barrier properties of organic coatings due to abrasion is studied by electrochemical impedance spectroscopy. The damage of organic coatings caused by abrasion impact of different abrasive materials and abrasion as a result of rubbing aggressive agents against the...
Polystyrene–acrylonitrile mixed with different carbon nanotube (CNT) fractions has been successfully prepared by means of in situ polymerization method. The tribological behaviors of the nanocomposites are investigated by friction and wear tester under dry conditions. Compared with the polystyrene–acrylonitrile, polystyrene–acrylonitrile–CNTs shows not only the lower friction coefficient but also...
Wear behaviors of Ag/Cu multilayers were evaluated and compared using nanoscratch techniques under a ramping load. Scratch grooves were examined using scanning electron microscopy (SEM) and in situ cross-section scan. It was found that the friction coefficients for all samples have significant difference and the wear resistance is not linearly proportional to the hardness. These discrepancies were...
The size and contact traction distribution present are found beneath a sphere, pressed into a contacting body and subject to oscillatory shear in the presence of wear. It is assumed that wear has proceeded until all partial slip has ceased, and the local state of stress around the final (adhered) contact disk are found explicitly.
For a given sheet metal forming process, an accurate determination of the contact pressure distribution is an essential step towards the estimation of tool life. This investigation utilizes finite element (FE) analysis to model and explain the evolution and distribution of contact pressure over the die radius, throughout the duration of a channel forming process. It was found that a typical two-peak...
In the last few years, a non-conventional ultrasonic approach has been proposed by the authors to experimentally assess the main contact parameters in wheel–rail systems. This technique, which is based on the analysis of the reflection of high frequency ultrasonic waves from the wheel–rail interface, makes it possible to obtain graphic maps from which we can observe the shape of the contact area,...
The fretting wear behavior of conventional and nanostructured Al 2 O 3 –13wt%TiO 2 coatings fabricated by plasma spray was studied in this paper. The conventional coatings were deposited with commercial Metco 130 feedstock, and the nanostructured coatings were deposited with agglomerated feedstock with nanostructure. There were typical lamellar structures existing in conventional...
An alternative carburization process, low-temperature colossal supersaturation (LTCSS), has demonstrated significant improvement on both wear- and corrosion-resistance for austenitic stainless steel surfaces in recent literature. This study explores the effects of multiple treatments of LTCSS on tribological characteristics for Type 316 stainless steel. Thicker carburized layers were produced by multiple...
Dry sliding wear behaviour of as cast, mushy state rolled Al–4.5(wt.%)Cu alloy and in situ Al–4.5(wt.%)Cu–5TiB 2 composite has been studied. Mushy state rolling has been performed on the cast alloy, and as cast or pre-hot rolled composite at temperatures corresponding to 10, 20 or 30vol.% liquid to reduction in thickness of 2.5, 5 or 7.5%. Wear tests carried out at loads of 19.6, 39.2, 58...
The influence of welded layers composition on the abrasive wear mechanism of friction couples “hard layer-steel” is analyzed. Strength, surface morphology, chemical and structural composition, abrasive wear resistance of welded layers are investigated. When cutting low carbon and chromium content layers with abrasive particles, the wear predominates there as it does under plastic deformation, while...
The effect of Si content on the wear properties of thixoformed AlSiCuFe alloys was investigated in the present work. Wear rates, which decrease with increasing Si content until 12wt%, start increasing at hypereutectic Si levels. The inferior wear resistance of thixoformed hypereutectic alloys is linked with the response of the coarse Si particles to severe wear conditions. The primary Si particles...
In the present study, both ultra-fine and coarse Al 2 O 3 –40wt.% ZrO 2 grains were used as the starting materials to prepare ultra-fine structured and micro-structured Al 2 O 3 –40wt.% ZrO 2 composite coatings (coded as NZTA coating and MZTA coating, respectively) by atmospheric plasma spraying. The ultra-fine Al 2 O 3 –40wt.% ZrO ...
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