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Sliding wear behaviour of some leaded-tin and aluminium bronzes has been studied over a wide range of applied pressures and speeds using a pin-on-disc machine. Wear rate, frictional heating and surface roughness of the samples were monitored during the tests. The wear response of specimens has been correlated with the features of their wear surfaces, subsurface regions and debris particles, and explained...
Both structure and phase transformations in subsurface layers as well as the tribological characteristics of WC+30wt.% Hadfield steel hard metal subjected to pulsed electron beam melting and then rubbed against a disk made of tool steel have been investigated. The melting was induced by a low-energy (10-40keV), high-current electron beam (2.5μS, 5-40J/cm 2 ). It has been established that the...
The effect of grain size of Al and dendritic arm spacing (DAS) of α-Al in Al-7Si alloy on wear behaviour of Al and Al-7Si alloy were investigated in the present study. The results show that the wear rate decreases with the decrease in the grain size and DAS of Al and Al-7Si alloy, respectively, at a load of 50N, sliding distance of 1800m and sliding velocity of 1ms -1 under dry sliding...
Tungsten carbide-cobalt based spray coatings are widely used in industry for applications requiring abrasion, sliding, fretting and erosion resistance. High velocity oxy-fuel (HVOF) flame spraying has been used for producing high quality carbide coatings. In this study, a WC-CoCr powder was sprayed using a HVOF process. The spray parameters were varied to study their influence on the particle in-flight...
A pin-on-disk test apparatus was modified to decrease the degree of misalignment between the pin end and the disk counterface. This was achieved by separate alignment of both pin and disk. Disk alignment was allowed by incorporating a kinematic three-ball arrangement into the disk under-face. A self-aligning pin alignment system was introduced which did not require the perpendicularity of the pin...
Erosion wear at the wetted passages is a critical parameter for selection and design of slurry transportation systems. Erosion wear is a complex phenomenon and is difficult to predict for multi-sized particulate slurries mostly due to representation of its dependence on a single particle size. In the present work, an effort has been made to develop a methodology to determine the nominal particle size...
If an isotropic rough surface is intersected with a plane near the highest points of the surface, the resulting intersection will comprise a set of approximately circular islands whose size distribution gives some information about the nature of the contact process for the rough surface. Statistical arguments are used to predict the distribution of line segment lengths obtained when a random straight...
The tribological properties of FeAl intermetallics under dry sliding against AISI52100 steel at ambient conditions were studied on an Optimol SRV oscillating friction and wear tester in a ball-on-disc contact configuration. Effects of load and sliding speed on tribological properties of the FeAl intermetallics were investigated. The worn surfaces of the FeAl intermetallics were examined with a scanning...
We have investigated the scratch resistance and the elastic modulus of the double-layered, the magnetic upper-layer and the under-layer films in order to clarify the scratch mechanism of the double-layered metal particulate media. The mechanical properties of the magnetic upper layer are superior to those of the under layer. The double-layered films were fractured by the generation and propagation...
A transient analysis for thermoelastic contact problem of disk brakes with frictional heat generation is performed using the finite element method. To analyze the thermoelastic phenomenon occurring in disk brakes, the coupled heat conduction and elastic equations are solved with contact problems. The numerical simulation for the thermoelastic behavior of disk brake is obtained in the repeated brake...
Piston skirt/cylinder bore scuffing is one of the main failure mechanisms affecting the life of automotive engines. A piston scuffing apparatus that simulates the relative motion between the piston and the cylinder liner of a typical engine has been designed and constructed to investigate scuffing mechanisms and determine the conditions under which scuffing happens. With this apparatus, the scuffing...
Since ductile fracture (rupture) is the process by which junctions are separated and which prevents ever-increasing plasticity and junction growth, it is argued that models of friction ought to include toughness as well as yield strength. An expression for the coefficient of sliding friction is derived using ductile fracture mechanics. The predictions are quite reasonable.
In the present paper, chromium white cast irons were prepared by the unidirectional solidification. The carbide sample was extracted for the corrosion and wear test. The inter-phase corrosion mechanism and the electrochemical behavior of chromium white cast irons in corrosion medium were discussed from the viewpoints of electrochemistry and erosion wear. The inter-phase corrosion rates between carbide...
Wear is one of the major causes of failure in many parts and components in gas-turbine engines. The fuel nozzle and its collar are two of the components that suffer rapid wear, in particular fretting wear at elevated temperature due to the vibration of the engine. The reported work was carried out to study the wear-resistant coatings for this application. Four types of coating, namely WC-17% Co, Cr...
Frictionally excited thermoelastic instability (TEI) is becoming of major concern in clutches and brakes as larger peripheral speeds and heat loads are required. Using the transient formulation proposed in Afferrante et al. [Wear 254 (2003) 136] and based on a perturbation method, the effect of a fairly general parabolic engagement law is investigated. Two damage parameters Φ 1 and Φ 2...
By means of the radionuclide technique ultra low wear rates were continuously measured in a pin-in-bushing tribometer with lubrication. In addition, friction and temperature were monitored simultaneously. Applying an energetic approach it was assumed that the total power dissipated in the tribological contact results mainly from heat flux, generation of wear and change of material with respect to...
Fretting wear is a destructive phenomenon that can accelerate crack initiation in vibrating components, leading to premature catastrophic failures. Among the most important characteristics of fretting, is the transition from mixed fretting wear to gross slip. Research has shown that mixed fretting wear is the most detrimental to fatigue life. In this paper, a study was conducted that characterized...
In recent machine structures, more and more ceramics are employed. Thus, in present study, a fretting wear phenomenon is observed between general-purpose ceramics and carbon steel. Three kinds of spherical specimens made of alumina ceramics (Al 2 O 3 ), zirconia ceramics (ZrO 2 ) and silicon nitride ceramics (Si 3 N 4 ) are tested. Their mating pair is a flat...
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