EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

One of the promising methods of microstructure modification in surface layers is a friction stir processing (FSP). This method is based on the basic principles of friction stir welding technology (FSW) however, the FSP method, unlike FSW, is used to modify the microstructure of the materials, and not to join metal elements. The process consists in heating and plasticizing the material as a result of the friction of a tool equipped with a shoulder and a pin plunged into the material and moving along the modified surface of the element. The movement of the tool causes heating, intense stirring, and densification of the deformed material.
In the study, the FSP method was used to modify the surface layer of a SnSbCu bearing alloy. The modification was aimed at extending the service life of bearings by improving their tribological properties.
The research carried out in this paper covered investigations of the microstructure using light and scanning electron microscopy along with analysis of the chemical composition in micro-areas, as well as Brinell hardness tests and uniaxial compression tests. Additionally, the phase composition was tested using X-ray diffractometer, the size of the precipitates present in the microstructure before and after the modification process was determined, as well as the tribological properties under technically dry friction conditions and lubrication with TU 32 oil.
It was proved that the use of friction stir processing for surface treatment of the SnSbCu bearing alloy causes significant changes in the morphology of the hard phases, including their refinement and improves the tribological properties of the analyzed alloy.