ICALEO 2005 Paper #1102 (Laser Clads for Application as Bearing Materials: Microstructure and Tribological Properties)
Rolf Galun, Institut fuer Werkstoffkunde und Werkstofftechnik, Technische Universitaet Clausthal; Clausthal, Zellerfeld Germany
Detlef Weinhausen, IWW; Clausthal-Zellerfeld Niedersachsen Germany
Gunar Bergmann, IWW; Clausthal-Zellerfeld, Niedersachsen Niedersachsen Germany
Presented at ICALEO 2005
Due to EU restrictions of using lead in materials for plain bearings in automotive applications, conventional lead bronze was replaced by materials based on lower strength and thus lower load bearing capable aluminium-tin alloys. Goal of the presented work was to produce bearing material layers of the system Al-Sn which have a higher strength compared to conventional Al-Sn bearing alloys. An increase of strength was realized by addition of third elements like iron, nickel and silicon. Addition of hese elements will result in the presence hard particles in the Al-Sn matrix by the formation of intermetallic phases with aluminum (Fe, Ni) or direct primary crystallisation of the hard Si. Due to limited formability of these materials, direct laser cladding is an ideal process for in situ production of plain bearings e.g. on crankshaft or gearbox housings made of aluminium alloys. In this work microstructure and tribological properties of different laser clads on aluminium substrates are presented. Microstructural evaluation showed generally a fine grained structure of the Al-Sn alloy, containing fine dispersed hard phases. Pin-on-disc wear tests showed superior wear behaviour of selected clads which makes them ideal candidates for use as materials in plain bearings.