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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...
Wear behavior of nanocrystalline (NC) AZ91D Mg alloy generated by surface mechanical attrition treatment and the corresponding coarse-grained (CG) samples subjected to dry sliding wear at different sliding velocities were investigated. The subsurface microstructure evolution of these two samples was analyzed by cross-sectional transmission electron microscope. The microstructure of NC layer was almost...
Metal fiber brushes are of interest in many high current density applications due to their high conductivity and low wear rates in humid environments. The frictional properties and wear behavior of a copper fiber brush sliding against a copper counterface in humid environments under high current densities (180A/cm 2 ) were investigated at low sliding velocities (10mm/s). A linear reciprocating...
Decoupled graphite lubrication of monolithic silver brushes on a copper rotor was studied in an ambient air environment under current varying from 0A/cm 2 to 200A/cm 2 using a custom designed electrical contact tribometer. Bifurcation of the positive and negative brush wear rates was observed at a current density of 200A/cm 2 . Energy dispersive spectroscopy showed transfer...
When nanoindentation is used for thin film characterization, the penetration of the indenter is usually limited to shallow indents to avoid the spurious effect of the substrate. However, the surface effects stemming from the sample surface topography and friction are the most pronounced in shallow indentation depths, potentially resulting in variations of the evaluated material parameters. A numerical...
A new high-entropy alloy system, AlCoCrFeMoNi, was designed based on the AlCoCrCuFeNi, by replacing Cu with Mo to improve strength and thermal stability. The effect of iron content on hardness and wear behavior of AlCoCrFe x Mo 0.5 Ni alloys is related to the microstructural change. As the iron content is increased, the microstructure changes from “dendritic” for Fe0.6 and Fe1.0 alloys...
Wear of etched near-eutectic aluminium–silicon alloy slid against a steel ball under ambient is explored. The sliding velocity is kept low (0.01m/s) and the nominal contact pressure is varied in a 15–40MPa range. Four stages of wear are identified; ultra mild wear, mild wear, severe wear and post severe oxidative wear. The first transition is controlled by the protrusions of silicon particles, projecting...
In the present investigation, tribological characteristics of spray formed and hot pressed Al–6.5Si, Al–12.5Si and Al–12.5Si–25Sn alloys have been studied. The alloys were spray formed in an environmental chamber using nitrogen gas at 1.0MPa gas pressure and a deposition distance of 350mm. The preforms were vacuum hot pressed, at appropriate temperatures, to achieve its densification, The spray formed...
A molecular dynamic simulation result is obtained for a nanoscale sliding layer system, with an emphasis on lattice structural changes and temperature variation induced by friction. A model for a stationary and moving layer of aluminum is analyzed at different sliding speeds. The model shows that the average temperature of the molecular structure increases rapidly during the transient period. The...
This study pertains to the examination of the effects of dispersing talc particles in an oil lubricant towards controlling the sliding wear characteristics of a journal bearing (bush) fabricated using a leaded-tin bronze. Influence of the content of the suspended mass in the oil and applied load on the wear behavior was also investigated. Properties evaluated were wear loss, frictional heating and...
Cavitation is a common phenomenon in fluid systems that can lead to dramatic degradation of solid materials surface in contact with the cavitating media. Study of cavitation damage has great significance in many engineering fields. Current techniques for cavitation damage study either require large scale equipments or tend to introduce damages from other mechanisms. In this project, we utilized the...
The present communication addresses the fretting corrosion behaviour of Ti–6Al–4V alloy in artificial saliva containing 0, 190, 570 and 1140ppm of fluoride ions. The fretting corrosion behaviour of Ti–6Al–4V alloy was evaluated based on the change in free corrosion potential (FCP) measured as a function of time. The wear morphology and surface profile of the fretted zone, assessed by scanning electron...
An innovative technique, friction stir processing (FSP) was employed for the fabrication of Al/Al 2 O 3 nano-composite surface layer on an Al alloy substrate. Aluminum work pieces with pre-placed nano-sized Al 2 O 3 powder which was filled in a shallow groove were subjected to various numbers of passes from one to four. Scanning electron microscopy studies showed that...
Micro-abrasive wear test, also called ball cratering test, is normally used to investigate the wear behavior of hard bulk materials or wear-resistant coatings. In this work, this test was used to investigate the wear behavior of metallic samples. The results showed that the embedment of abrasive particles and the formation of grooves in the crater's surface may induce to artificially small wear coefficient...
Computational tools are emerging as design tools for the development of total joint replacement with improved wear performance. The current wear models of polyethylene assume that wear is linearly proportional to sliding distance; however, it is hypothesized that the wear rate varies and is higher near a change in direction, but diminishes with continued unidirectional sliding, which eventually exhibits...
Wear resistance of the ZE41A magnesium alloy was tested using pin-on-disc technique and steel as counterbody on dry sliding conditions. Wear rates and friction coefficients were measured in a sliding velocity range of 0.1–1ms −1 and in a normal forces range of 5–40N. Worn tracks and wear debris were studied by scanning electron microscope (SEM) and energy dispersive X-Ray spectrometer (EDX)...
Dry sliding tribological behaviors of nanocrystalline (NC) and coarse grained (CG) Cu were studied by using a ball-on-plate tribometer with a counterface ball of cemented tungsten carbide. The results showed that prior to oxidation and delamination, the steady-state friction coefficients (FCs) of NC and CG Cu are comparable (∼0.35). As oxidation with delamination of wear surface occur, the FC for...
A simple mathematical expression is presented to describe cavitation mean depth of erosion versus time for cavitating jets and ultrasonic cavitation. Following normalization with a characteristic time, t*, which occurs at 75% of the time of maximum rate of erosion, and a corresponding material characteristic mean erosion depth, h*, the normalized erosion depth is related to the normalized time by...
Sliding contact under high pressure between a more or less rough metal surface and a polymer occurs in diverse manufacturing processes. Transfer of the softer material on the harder counterpart is a common phenomenon under such conditions (high pressure) due to high level of polymer wear. The transfer of worn polymer particles on the metal surface generally has a large influence on friction. A model...
Under certain conditions, the metals of some heavily loaded tribological units may slide against each other without the benefit of lubrication. In such cases, the heat or electrical conduction properties of the sliding materials are particularly important. Copper-based materials are relevant for such application. In this study, we investigated the wear and friction that occurs between copper-based...
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