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Fretting is defined as a small displacement oscillatory motion between two solids in contact. Depending on the loading conditions (displacement amplitude, normal force, etc.) fretting damage can be induced by surface adhesion, abrasion, and fatigue with debris formation and ejection being the by products of wear.For the studied titanium alloy Ti–6A1–4V, fretting conditions were reproduced through...
To investigate the effect of hydrophobic surface on cavitation damage, hydrogen-terminated diamond film and oxygen-terminated diamond film are prepared for the cavitation damage experiment. Because the film surfaces have the same roughness and hardness, the hydrophobic property effect is focused on. Obvious damage pits appear on the hydrogen-terminated surface after 4h cavitation experiment, while...
A large percentage of apples are wasted each year due to damage such as bruising. The apple journey from orchard to supermarket is very complex and apples are subjected to a variety of static and dynamic loads that could result in this damage occurring. The aim of this work was to use a novel ultrasonic technique to study apple contact areas and stresses under static loading that may occur, for example,...
In the present study, an attempt was made to examine the synergic effect of SiC particle reinforcement and heat treatment on the two body abrasive wear behavior of an Al–Si alloy (BS: LM13) under varying loads and abrasive sizes. Silicon carbide particles with size 50–80μm were reinforced in Al–Si alloy, in varying concentration (10wt% and 15wt%), by solidification process (vortex technique) and the...
Electrodeposited nanocrystalline nickel–tungsten alloys are being investigated as an attractive alternative to electrodeposited nickel for applications involving fabrication of micro electro mechanical systems (MEMS). Ni–W alloys are also being considered as an environmentally friendly alternative to hard chrome plating in some cases. In applications involving sliding contacts such as in micro-gears...
Improvement in cored wire composition and fabrication has made possible the application of wear resistant coatings using the attractive twin wire arc thermal spray technique. In the present work, different wear resistant coatings named Alpha 1800, Armacor M and Ducor were deposited using TAFA 9000 wire arc spray equipment for their application in atmospheric fluidized bed combustion boilers. The erosion...
This paper presents a mathematical model for kinetics of abrasive wear of concrete. The underwater method ASTM C1138 was used to test the abrasive wear. The paper includes the results for high performance concrete (HPC) and a description of water/cement ratio (w/c) influence on the abrasive wear of HPC under constant load. The influence of load on a concrete wear through the variation of speed of...
Simple upper bound plastic mechanisms are developed to relate the pressure and contact area for a partially flattened sinusoidal profile. The resulting surface deformation is calculated, and the results are compared with the elasto-plastic simulation results of Gao, Bower, Lev and Cheng. A lower bound stress field solution is also developed to show that the assumption of rigid-perfectly plastic behaviour...
In this paper studies on the wear of brushes against copper commutators were briefly reviewed. The effects of alternate current density and humidity on the wear rate of electrographite brushes were investigated and the wear mechanism was discussed in detail. SEM (scanning electron microscope) and EDS (energy dispersive X-ray analysis) were used to observe the morphology of contact surface of brushes...
The potential of non-destructive and non-contact thermal wave methods to measure and to quantify the effects of friction wear on coated surfaces is analyzed by measurements of coated cutting tools using modulated IR radiometry. The thermal wave signals, measured as a function of the heating modulation frequency for hard coatings on tool steel without and with friction wear effects, are interpreted...
Plasticine strips are rolled between cylindrical rollers to model the phenomenon of material transfer in metal rolling. Strips of thin plastic film (‘clingfilm’) on the plasticine strip are used to model the oxide layer that covers the surface of aluminium. The effect of gaps opening up between the clingfilm strips is investigated. It is found that the percentage area of the exposed strip giving rise...
A method for determination of an optimum railway vehicle wheel profile for a given geometric contact characteristics of wheel/rail using a numerical optimization approach is presented in this paper. Such characteristics are defined through a given rail profile, and the target rolling radii difference (Δr) as a function of lateral displacements (Y). Cubic spline functions are utilized to connect curve...
The friction, wear and acoustic emission properties of POM, PA 66, torlon, PP, PTFE, HDPE and PVC sliding against silicon nitride, Si 3 N 4 , were studied using a ball-on-flat-rotating-disc tribometer. The friction and normal forces were measured in real time to accurately determine the dynamic coefficient of friction COF. Wear of the weaker material was quantified by the loss in volume...
Thick alumina coatings were performed on A356/20vol.% SiCp composites by micro-arc oxidation (MAO) process with different processing time. MAO-coated layer is composed of α-alumina, γ-alumina and mullite, and the hardness value increases and then decreases sharply with distance from the interface. The dry sliding wear tests were performed on A356/20vol.% SiCp composites with and without surface coating...
Milled carbon fibre reinforced epoxy gradient composites were developed at different centrifugation speeds having 3wt% of milled carbon fibre. Composites were also prepared at different RPMs. There is a gradient formation at all the speeds, which has been confirmed by variation in density of different zones. Highest rpm centrifuged sample gave best wear resistance as compared to others up to transition...
Titanium alloys, due to their excellent combination of low density, high strength to weight ratio, high corrosion resistance and biocompatibility, are widely used in the aerospace, automotive, chemical and biomedical industries. However, a main limit to the use of Ti alloys is their poor tribological behaviour. For this reason, different surface treatments and coatings have been developed for improving...
Pellets were formed by compacting MoS 2 powder. A series of tests were conducted on a tribometer that consisted of simultaneous pellet-on disk and pad-on disk sliding contacts. The purpose of the tests was to intentionally transfer MoS 2 third-body particles to a disk where its lubrication characteristics could be studied. This work also showed that the MoS 2 pellet actually...
Studies are focused on the composites using carbon fabric (CF) as a reinforcement and high performance thermoplastic polyetherimide (PEI) as a matrix. Based on impregnation technique three composites viz. P, T and S were fabricated using three different weaves viz. plain (P′), twill (T′) and satin 4H (S′), respectively, keeping the fabric content constant (55% by vol.). Apart from evaluating physical...
This work investigated the effect of zircon particle size on the friction characteristics of brake lining materials. Four different sizes of commercially used zircon particles (nominally 1μm, 6μm, 75μm, and 150μm in diameter) were used to produce non-steel type lining materials. We focused on the level of the friction coefficient, the oscillation of friction force, and wear resistance of the linings...
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