Work presented at 2000 AIMETA Tribology Conference in L'Aquila (Italy), September, 20-22th 2000.

0.1 Abstract

Ferrous porous alloys, produced by Powder Metallurgy (PM), are currently used in the production of structural parts, like gears, which undergo rolling-sliding loading in service. In order to increase employment of these types of materials, specific design criteria which properly account for the damage mechanisms have to be developed. In the present investigation the lubricated rolling-sliding surface damage mechanisms in whole as-sintered and carbonitrided PM materials were investigated. Four types of damage mechanisms were identified: surface densification; formation of surface microcracks by asperity-scale plastic shearing; formation of numerous microcracks at the pore edges; formation of subsurface macroscopic cracks, which produced spalling. The influence of microstructure on the occurrence of such mechanisms is discussed, and guidelines for the proper selection of PM materials for lubricated rolling-sliding applications are thus highlighted.

0.2 Index of essay

0. Abstract
1. Introduction
2. Experimental procedures
3. Results and discussion
4. Conclusions
5. References