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Because particulate reinforced metal matrix composites cannot be welded without unacceptable disruption of local particle distribution and matrix microstructure, they are normally joined using mechanical fasteners or adhesives, and consequently they are susceptible to fretting wear and fretting fatigue. The fretting wear behaviour of a 2124 Al-Cu-Mg alloy reinforced with a uniform distribution of...
Material transfer is a common phenomenon in dry friction, generally associated with a change in surface topography and in frictional interactions. In previous work, the actual influence of adhesion, cohesion and interfacial shear stresses on the extent of transfer (the transfer being assessed experimentally by image analysis) was established both on a theoretical and experimental basis, but at constant...
Surface engineering techniques are being considered in the hot forging industry, for improving the life of forging dies. During forging, the surfaces of the dies reach temperatures of 700-800°C. Published information on the wear performance of modified/engineered surfaces at higher temperatures is, however, scarce. To address this situation, a high-temperature pin-on-disc machine was modified into...
Engineered injection molded plastics are now common substrates of choice for painted bumper fascias in the automotive industry. A major challenge for painted fascias involves potential warranty costs associated with various tribological scenarios that can result in moderate to severe paint delamination. Preliminary failure analysis performed on field specimens indicate surface damage in majority of...
A unidirectional silicon carbide continuous fibre reinforced calcium aluminosilicate (CAS/SiC) glass-ceramic matrix composite has been subjected to silica sand solid particle erosion over the temperature range 20 to 726°C. At room temperature, tests were conducted at two velocities. The lower (7 m s -1 ) did not generate lateral cracks and a wear rate of 0.004 mg g -1 was...
Dry sliding tests were carried out under different load and sliding speed conditions on Ti-6Al-4V alloy plasma nitrided at three temperatures: 973, 1073 and 1173 K. The results were interpreted on the basis of the evolution of the friction coefficient and by characterizing the wear debris and worn surfaces in order to understand the acting wear mechanisms. A comparison was also made with the results...
When a hard rough surface slides repeatedly on a softer component a system of protective residual stresses may be developed in the near-surface layers of the weaker material which enable loads sufficiently large to cause plastic deformation in the early cycles of loading to be accommodated purely elastically in the later stages of the loading history. This is the process known as shakedown and limits...
The friction and wear characteristics of zinc-based alloys in warm, oil-lubricated, sliding contact against mild steel were investigated. The alloys, their compositions, and their microstructures included: pure Zn (100% Zn, η zinc), Zamak 3 (Zn-4Al-O.1Cu, η zinc plus η/α eutectic), ZA 27 (Zn-31Al-2.3Cu, α aluminum plus η/α eutectic), ACuZinc 5 (Zn-3.0Al-5Cu) in die cast form, and ACuZinc 10 (Zn-3...
Zirconia ceramics with different dopants, used to retain the tetragonal phase metastably, were evaluated to determine the effect of the difference in degree of transformability on the abrasive wear behavior. The abrasive wear tests, carried out on a multiple abrasive wear tester, showed that for two-body and three-body configurations the wear rate increases for higher normal loads and abrasive grain...
High-strength bainitic steels have a number of desirable mechanical properties and have thus been viewed as candidate materials for heavy wear applications. This work examines the role of transformation temperature on the wear resistance of isothermally formed bainite from a single alloy steel and compares it with wear resistance following other heat treatments such as quenching, quenching and tempering...
The crossing of the electric current in rail lines through a copper/steel sliding contact is associated with an electric field between the sliding surfaces. The electric field increases with the current intensity, the sliding speed and the contact resistance, and it decreases with an applied normal load. An electric field enhances the oxidation of surfaces, and the growth of such an oxide layer increases...
This study investigates the effects of solid and liquid lubrication on the friction and wear performance of silicon nitride (Si 3 N 4 ) and gray cast iron. The solid lubricant was a thin silver film (∼ 2 μm thick) produced on Si 3 N 4 by ion-beam-assisted deposition. A high-temperature polyol-ester-base synthetic oil served as the liquid lubricant. Friction and wear...
An investigation was performed to study the factors affecting the transition between fretting and reciprocating sliding wear using a new technique in which a transparent (sapphire) disc is rubbed against a steel sphere under both lubricated (hexadecane) and dry conditions. The technique allows direct observation of the wear occurring in the contact as well as the appearance, size and transport of...
Frictional characteristics in response to changes of the dynamic parameters of a pin-on-disk apparatus were experimentally and theoretically investigated for dry sliding. The apparatus has been designed and built to allow control of sliding speed, load, stiffness and loading mechanism. Dynamic friction and normal force were measured for various conditions of the system parameters, e.g. different stiffness...
Although the wear of ultrahigh molecular weight polyethylene (UHMWPE) total joint implant components has received much attention, the creep of this polymer has been inadequately studied. The objectives of this study were to determine whether creep affects the wear of UHMWPE and, if so, to measure the magnitude of this effect. Cylindrical specimens were machined from GUR 4150HP extruded unirradiated...
The abrasive wear of brittle materials, while not a true property of materials, is generally modeled as an inverse function of both the bulk hardness and fracture toughness. According to these models, an increase in the hardness and/or fracture toughness of a material will therefore enhance its wear resistance. In ceramic materials, the addition of whisker reinforcement is a proven method of enhancing...
An investigation has been carried out into the manufacture and field trial of alloy white iron beater plates used to process coal in a KSG coal pulveriser mill. The components were made by the cast bonding process, which involves casting a wear layer onto a steel substrate to form a bimetallic composite product. Four alloy white irons, containing primary and/or eutectic carbide volume fractions ranging...
The subsurface microstructures induced by dry unidirectional sliding wear of as-cast and heat treated Al-Si alloys reinforced with 20 vol.% SiC particles against a tool steel ring were investigated by cross-section transmission electron microscopy (XTEM). The subsurface characteristics were related to the wear behavior of both the as-cast and heat treated composites. In particular, an in situ precipitation...
A study has been made of the critical variables of particle type and size, flux and velocity on the erosion of a 1Cr Mo boiler tube steel up to temperatures of 600°C in a purpose-built air-blast laboratory rig. Whilst particle type has a slight effect on wastage, particle size, flux and velocity affect the magnitude of the erosion rate significantly.
The ability to deposit metal matrix composite (MMC) coatings on the surface of aluminium alloys has the potential to expand the engineering applications of these materials. Composite coatings reinforced with discontinuous ceramic particles enhance the substrate's tribological properties. In applications where dry sliding or low stress abrasive wear processes predominate, these coated aluminium alloy...
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