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Keynote Papers

2005;():3-4. doi:10.1115/WTC2005-64231.

The production of nanocrystalline wear debris containing components from the worn specimen, from the counterface and from the environment does not support any of the better known wear models or wear equations based on adhesion, delamination, fatigue or oxidation. In this presentation, plastic deformation, mechanical mixing and patterns of flow determined from experiments will be compared with molecular dynamics (MD) simulations and a continuum analysis of two ‘fluids’ shearing in opposite directions. Together, these suggest generic behavior that needs to be included in any realistic sliding wear model.

Topics: Wear
Commentary by Dr. Valentin Fuster
2005;():5-6. doi:10.1115/WTC2005-64273.

The traditional classification of abrasive wear into two-and three-body, high and low stress, open and closed etc. does not recognise the essential importance of particle motion, which is better described as either sliding or rolling. Abrasive wear tests with free abrasives can produce either type of motion, depending on the test conditions. The widely-used dry sand rubber wheel test often produces both motions over different areas of the sample. The more recent micro-scale abrasion test tends to favour one or the other over most of the wear scar area. Analytical models can be developed which allow the dominant particle motion to be predicted, and mapped using readily accessible parameters. In erosive wear, particle motion can also be important; recent work suggests that particle rotation is imparted in some types of erosive wear test, and that it may be responsible for the differences in wear rate found in tests under nominally identical conditions with different designs of apparatus. It is suggested that in the use of laboratory abrasion and erosion tests, and in the analysis of practical instances of wear by hard particles, close attention should be paid to the nature of particle motion, since this will influence both the dominant wear mechanisms and also the wear rates.

Commentary by Dr. Valentin Fuster
2005;():7-8. doi:10.1115/WTC2005-64396.

Focused ion beam (FIB) microscopy has been available for over 20 years, but substantial improvements in recent years has delivered a powerful technique for the study of surface structures. Ion channeling contrast, produced by secondary electron emission from the Ga ion interaction with the surface is a high sensitivity, high resolution technique for revealing phase distributions and deformed structures. Moreover, the ion beam can be used to take sections of the worn surface for subsequently removal for TEM. Despite the major advantages of ion channeling contrast and 3-D sectioning, the technique has only recently been applied to worn surfaces. This paper demonstrates the power of the technique in the study of the worn surface of 3 very different materials, namely 1) Al-alloy metal matrix composites, reinforced with MoSi2 and CrSi3 , worn under lubricated sliding, with very low wear rates; 2) hot rolled aluminium alloys, where the surface structure leads to enhanced Filiform corrosion, and finally 3) the worn surface of TiAlN/VN multilayer coatings, where friction induced oxide formation results in significant changes in friction coefficient.

Commentary by Dr. Valentin Fuster

Wear of and Fatigue of Materials

2005;():9-10. doi:10.1115/WTC2005-63016.

The Al-TiC composites containing three different volume fractions 0.07, 0.12 and 0.18 of TiC have been fabricated and wear characteristics of Al-TiC composites have been investigated under dry sliding. Dry sliding wear tests have been carried out using a pin-on-disk wear tester at normal loads of 9.8, 14.7, 19.6 and 24.5 N and at a constant sliding velocity of 1.0 m/s. Th