The Influence of Temperature on Failure Development in Steels Under Transition to Seizure

1996 ◽  
Vol 118 (3) ◽  
pp. 527-531 ◽  
Author(s):  
L. Rapoport
Keyword(s):  
Wear Mechanisms ◽  
Skin Effect ◽  
Oxide Films ◽  
Disk Surface ◽  
Wear Particles ◽  
Temperature Model ◽  
Mechanical Instability ◽  
Infinite Body ◽  
Temperature Instability ◽  
Adhesion Interaction

Seizure phenomena in pin-on-disk tests have been studied for “soft” and “hard” steel specimens. Differences in competing and dominant wear mechanisms under steady state friction have been preserved for “soft” and “hard” specimens in the region of transition to seizure or galling. Severe wear was observed for “soft” specimens under all loads tested, while adhesion and splitting off of wear particle conglomerates (microseizure) were identified for “hard” specimens. The contact temperature, calculated in accordance with the temperature model of plastically deformed contact spots (Kuhlmann-Wilsdorf), has appeared to be low for “soft” specimens and not sufficient for adhesion interaction. The effect of oxide films on the friction of “hard” specimens has been estimated in accordance with the temperature model for a coated semi-infinite body (Tian and Kennedy). The insulated oxide films on the surface of “hard” specimens create the “skin effect” and lead, therefore, to raising the temperature up to the temperature of adhesion interaction. Temperature instability of hard surfaces has been demonstrated to result from the “skin effect” and from a disturbance in equilibrium of formation and failure of oxide films. It has been shown that for “soft” specimens the prime cause of transition to seizure was the mechanical interlocking between the wear particles and the soft disk surface combined with mechanical instability, while for “hard” specimens the cause was temperature instability. A more realistic temperature model of the contact has been considered, which takes into account some competing wear mechanisms (oxidational wear, ploughing, delamination) and the effect of wear particles.

Nano-Scale Fatigue Wear of Carbon Nitride Coatings: Part II—Wear Mechanisms

2003 ◽  
Vol 125 (2) ◽  
pp. 437-444 ◽  
Author(s):  
Dong F. Wang ◽  
Koji Kato
Keyword(s):  
Wear Mechanisms ◽  
Carbon Nitride ◽  
Low Cycle Fatigue ◽  
Surface Flow ◽  
Theoretical Expression ◽  
Asperity Contact ◽  
Wear Particles ◽  
Critical Number ◽  
Fatigue Wear ◽  
Nitride Coatings

This is the second part of two companion papers, the first of which reported the empirical data on wear properties in carbon nitride coatings by a spherical diamond counter-face in repeated sliding contacts through in situ examination, with an emphasis on the effect of friction cycles and normal load. The second part will concentrate on wear mechanisms for the transition from “No observable wear particles” to “Wear particle generation.” The relationship between the critical number of friction cycles, Nc, and the representative plastic strain, Δεp, at asperity contact region was confirmed to follow the Manson-Coffin equation with two empirical constants, β and C. The observed generation of wear particles in carbon nitride coatings is therefore concluded to be a low cycle fatigue wear by surface flow and surface delamination in the ploughing mode. For further predicting lifespan, a simplified theoretical expression, combining the Manson-Coffin equation with the analytical solution of a proposed elastic perfectly-plastic indentation model, gives the relation between the critical number of friction cycles, Nc, and the coating thickness h, with respect to the contact pressure P, and the radius R of the asperity on the tip of the diamond pin.

Characterization of wear particles for comprehension of wear mechanisms

Wear ◽  
2008 ◽  
Vol 265 (11-12) ◽  
pp. 1714-1719 ◽  
Author(s):  
C. Kowandy ◽  
C. Richard ◽  
Y.M. Chen
Keyword(s):  
Wear Mechanisms ◽  
Wear Particles

Toward a Mechanical Wear Equation

1983 ◽  
Vol 105 (2) ◽  
pp. 212-219 ◽  
Author(s):  
J. Halling
Keyword(s):  
Film Thickness ◽  
Simple Form ◽  
Material Properties ◽  
Wear Mechanisms ◽  
Wear Behavior ◽  
Linear Wear ◽  
Surface Films ◽  
Wear Particles ◽  
Asperity Distribution

It is first shown that the simple form of linear wear/load relation of the adhesive and abrasive wear laws arises from the nature of the asperity distribution. Without recourse to specific wear mechanisms, simple concepts for material properties, size of wear particles, and the production of wear particles are introduced. This procedure leads to an increasing appreciation of those factors which might be embraced by the specific wear constant. Of particular interest is the role of ductility in wear behavior. Finally, these ideas are extended to deal with the wear of surface films where it is seen that the film thickness is of paramount importance. Some experimental evidence for the concepts used is also provided.

scholarly journals Effect of CoCr Counterface Roughness on the Wear of UHMWPE in the Noncyclic RandomPOD Simulation

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Vesa Saikko ◽  
Vesa Vuorinen ◽  
Hannu Revitzer
Keyword(s):  
Wear Mechanisms ◽  
Wear Test ◽  
Test System ◽  
Random Motion ◽  
Wear Particles ◽  
Knee Prostheses ◽  
Ultrahigh Molecular Weight ◽  
Computer Controlled ◽  
Pin On Disk ◽  
Counterface Roughness

With the random motion and load pin-on-disk (RandomPOD) wear test system, conventional and highly crosslinked ultrahigh molecular weight polyethylenes (UHMWPE) were run against CoCr counterfaces with different surface roughnesses. The unique 16-station, computer-controlled pin-on-disk device produced noncyclic motion and load. With appropriate specimen shapes, simulations of wear mechanisms of both hip and knee prostheses were performed. Against polished counterfaces, the crosslinked UHMWPE showed negligible wear. Its wear against severely roughened counterfaces was close to that of conventional UHMWPE against polished counterfaces. The reduction in wear with crosslinked versus conventional UHMWPE was 80–86% in the hip and 87–96% in the knee wear simulation. The wear particles were of clinically relevant size and shape which indicated realistic wear mechanisms.

scholarly journals A Review on the Study of the Generation of (Nano)particles Aerosols during the Mechanical Solicitation of Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Neeraj Shandilya ◽  
Olivier Le Bihan ◽  
Martin Morgeneyer
Keyword(s):  
Broad Spectrum ◽  
Wear Mechanisms ◽  
Interdisciplinary Studies ◽  
Nano Particles ◽  
Wear Particles ◽  
Potential Health ◽  
Particle Generation ◽  
Modeling Techniques ◽  
Material Sciences ◽  
Stress Application

This paper focuses on presenting the forefront of the interdisciplinary studies conceived towards the generation of the wear particles aerosol when materials are subjected to mechanical stresses. Various wear mechanisms and instrumentation involved during stress application and aerosolization of wear particles, as well as particles characterization, measurement, and modeling techniques are presented through the investigation of a series of contextual works which are emphasized on the identification of these aspects. The review is motivated from the fact that understanding mechanisms involved in wear-induced particle generation, both at nano- and at microscale, is important for many applications that involve surfaces sliding over each other due to various potential health aspects. An attempt has been made to explain how the information based on this broad spectrum of subjects discovered in this contribution can be used and improved in order to produce a more resilient, rational, and versatile knowledge base which has been found lacking in the present literature during its survey. The area of study is highly multidisciplinary since it involves aerosol, particle, and material sciences.

Resolving Crystallites in Zirconium Oxide Films

1969 ◽  
Vol 27 ◽  
pp. 140-141
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscope ◽  
Inelastic Scattering ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Optic Axis ◽  
Objective Lens ◽  
Microscope Objective ◽  
Linear Optic ◽  
A Current ◽  
Microscope Objective Lens

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.

Analysis of Sputtered Zinc Oxide Films

1980 ◽  
Vol 38 ◽  
pp. 416-417
Author(s):  
T. A. Emma ◽  
M. P. Singh
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Piezoelectric Materials ◽  
Oxide Films ◽  
Optical Quality ◽  
Zno Films ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Sputtered Films ◽  
Zinc Oxide Films

Optical quality zinc oxide films have been characterized using reflection electron diffraction (RED), replication electron microscopy (REM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Significant microstructural differences were observed between rf sputtered films and planar magnetron rf sputtered films. Piezoelectric materials have been attractive for applications to integrated optics since they provide an active medium for signal processing. Among the desirable physical characteristics of sputtered ZnO films used for this and related applications are a highly preferred crystallographic texture and relatively smooth surfaces. It has been found that these characteristics are very sensitive to the type and condition of the substrate and to the several sputtering parameters: target, rf power, gas composition and substrate temperature.

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