The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Correlation of Material Characteristics and Wear of Powder Metallurgical Metal Matrix Composites
Päivi Kivikytö-Reponen
Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Materials Science and Engineering for public examination and debate in Auditorium 1 at Helsinki University of Technology (Espoo, Finland) on the 1st of December, 2006, at 12 o'clock noon.
Dissertation in PDF format (ISBN 951-22-8479-0) [4451 KB]
Dissertation is also available in print (ISBN 951-22-8478-2)
Abstract
The wear of materials is a major and widely recognised industrial problem. The direct costs of wear failures, i.e., wear part failures and replacements, increased work and time, loss of productivity, as well as indirect losses of energy and the increased environmental burden, are real problems in everyday work and business.
In this study, the materials of interest are wear-resistant powder metallurgical metal matrix composites, MMCs. Powder metallurgical, P/M, production of material, involving, for example, hot isostatic pressing (HIPing), offers considerable potential for enhanced wear resistance because it has a larger capacity to modify microstructures than conventional production technologies. Martensitic- and tool-steel-based composites were studied with reference to the needs of the mineral industry, while the wear of austenitic- or duplex-steel-based composites was evaluated with reference to those of the energy industry. The wear was studied both in functional wear tests involving a small-scale cone crusher, as well as in laboratory tests, such as the dry sand rubber wheel and erofuge tests.
The correlation between the wear behaviour and the material-related parameters of the steel-based metal matrix composites was investigated. The material-related parameters were microstructural parameters, such as the volume fraction of the reinforcements and hard particles, the size of the reinforcements, the true carbide size of the hard particles and spacing between the reinforcement particles. These parameters are evaluated by varying the matrix material of the composite and by varying the reinforcements in the fixed matrix material. The significantly important parameters that have an effect on the material wear rate were identified. The most important reinforcement-related parameters in these wear environments were the total volume fraction of the hard phase, the spacing between hard particles and the type of the hard phase.
Keywords: abrasive wear, cone crusher, wear resistant materials, metal matrix composites
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© 2006 Helsinki University of Technology
Last update 2011-05-26