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Surface asperities take a large part of a thin blank in micro-sheet forming processes. Contact and friction significantly affect micro-sheet forming and cannot be simplified as homogeneous in simulation. Material heterogeneity of the blank further affects the friction and its impact becomes significant in micro-scale. In this study, a FE model representing surface morphology of SUS304 sheets was built...
Friction and wear behavior of a thermoplastic polyimide (PI) and its mesoporous silica (MPS) reinforced nanocomposite was investigated at temperatures up to 300°C in dry sliding against GCr15 steel. Experimental results showed that elevated temperature produced significant promoting effect on the tribological properties of pure PI. Specific wear rate of the PI at temperatures up to 300°C was reduced...
Railway wheel-rail contacts involve various combinations of slip, rolling, and creepage. Traditionally, a twin-disc apparatus is used to simulate such problems. However, there are out of plane forces and motions involved in the actual situation. Therefore, the possibility of using a commercially-made, inclined-axis spinning ball-on-disc test rig was investigated to better simulate wheel and rail contact...
During producing silicon surface and fabricating silicon devices, the machining, cutting and milling from nanoscale to macroscale are accomplished with friction and wear under single- and multiple-asperity contact. In the present study, the scratch tests on silicon surface under single- and multiple-asperity contact were contrastively investigated, and the transition and correlation between different...
New bearing materials for total joint replacement have been explored as the need to improve longevity and enhance performance is driven by the changing demands of the patient demographic. Carbon-reinforced PEEK has demonstrated good wear characteristics in experimental wear simulation in both simple geometry pin-on-plate studies and in total hip joint replacement. Carbon reinforced PEEK CFR-PEEK has...
The wear of car brakes is one of the main sources of airborne particulate matter in urban environments. Ultrafine wear particles are of special environmental interest since they can easily penetrate the human body through inhalation and cause various diseases. In the present study, the contribution of ultrafine particles to airborne particulate matter emitted from car brake materials was investigated...
The wear response of tungsten carbide-iron aluminide (WC-FeAl) cutting tools was compared to that of conventional cemented carbide (WC-Co) tools when dry machining oxygen-free copper (Cu) round bars. Using flank wear width as a metric, it was found through machining tests that WC-FeAl cutting tools exhibited longer lifetimes (30% longer) than WC-Co ones with the same cutting distance. It was proposed...
Triboemission – i.e. the emission of photons, electrons and other charged particles that arise from a sliding contact – may play a key role in tribochemical processes, such as lubricant degradation. However, the mechanisms that give rise to this type of emission are not well understood. For the first time, we present spatially resolved measurements of electron emission, obtained as a range materials...
Tool crater wear is a major cause of accelerated tool failure during the machining of titanium alloy components. This paper presents a static diffusion couple method which replicates the complex reaction mechanisms occurring at the tool-chip interface during machining and is validated with dynamic turning trials. The diffusion couple tests are realised via the use of a bespoke vacuum compression rig...
Mechanical and tribological properties of barium boroaluminosilicate glass (commercial AF45® glass) treated with a thermal poling process employing 4kV bias at 600°C were studied. Compared to the pristine AF45 glass, the anode-side surface of the thermally poled glass has lower modifier ion concentrations and lower reduced modulus and hardness, while the cathode-side surface has increased modifier...
In this study, the etch rate (ER) and the removal rate (RR) of germanium using oxone based silica chemical mechanical planarization (CMP) slurries have been investigated. In the dissolution study, the Ge ER was found to increase with increase in pH from 3 to 11. It was also observed that Ge ER increased initially with oxone concentration and then levelled off. The dependency of Ge RR on oxone concentration,...
The effects of the abrasive particle size and the pH-value of the aqueous solution on the abrasive wear resistance of H–13 steel and Hadfield steel were investigated. Abrasive wear tests, using a wet rubber wheel abrasion tester, were carried out applying abrasive sizes in the range of 0.15–2.40mm. The pH-values of the aqueous solution ranged from 5.5 to 12.8. The microstructure of each material was...
Lubrication properties and mechanisms of various oxygenated compounds, carboxylic acid, aldehyde, alcohol, ketone, ester, and ether, were investigated. The high-frequency reciprocating rig was used to measure the lubricity. The effects of functional group, humidity, and carbon-chain length on the lubricity of the oxygenated compounds were studied. After the lubricity test, microscopic observation...
Cavitation erosion causes serious problems for hydraulic machinery. Selective laser melting (SLM), is a type of additive manufacturing that can produce metal parts directly and it has begun to be used in various industrial settings. However, the erosion properties of the SLM processed parts have only rarely been reported. The paper addresses the cavitation erosion behavior of AlSi10Mg samples fabricated...
Erosion-corrosion tests were carried out at two regimes, non-swirling jets with swirl number (S=0), and weakly swirling jets up to reaching vortex breakdown (S=0.1, 0.2 and 0.3); the average flow velocity was adjusted at 3.2ms−1, meanwhile the corrosive media consisted of 1l of distilled water and 2g/l NaCl purged with CO2 and abrasive particles of 20μm of aluminium oxide (Al2O3) suspended into test...
Proper lubricants and lubrication methods for rolling bearings are essential for providing sufficient bearing performance in high pressure applications. Main roles of molybdenum disulfide (MoS2) grease lubricant in rolling bearing are reduction of friction and wear, removal of frictional heat, extension of fatigue life, and protection from corrosion. Traditional method to evaluate wear behaviour of...
By using an atomic force microscope, the nanowear tests of Si(100) surface against SiO2 microsphere were performed both in humid air and in water. The experimental results indicated that mechanical interaction could significantly enhance the tribochemical wear of Si/SiO2 pair. There existed a threshold pressure (~1.1GPa) for tribochemical wear under one sliding cycle at 50% RH, which was much less...
This paper details a novel method to characterize and quantify edge wear patterns in ceramic-on-ceramic acetabular liners using a roundness measurement machine to measure the post-wear surface. A 3D surface map is produced which encompasses the measured surface covering the wear patch, the uncontrolled edge geometry and form of the bearing surface. The data is analysed to quantify linear penetration...
Friction experiments were carried out sliding a fingerpad, in both a bare state and with a latex glove donned, across a force plate to determine friction levels for different contact surface conditions (dry/wet; steel/glass). Donning a glove was found to increase the friction in dry conditions, but reduce it in wet conditions. A range of vibration frequencies were found to occur during sliding and...
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