Wear Regimes of Hot-Extruded Babbitt-Based Composites

Abstract

The paper deals with the effect of Ti₂NbAl intermetallic additives on the friction processes of hot-extruded B83 babbitt specimens. Optical and electron microscopy and energy-dispersive analysis were used. The structure, friction surface, and wear products were studied. Tribological tests were performed under dry sliding friction conditions using a universal testing machine according to an axial loading scheme of a steel sleeve to a disk made of the test material. The values of temperature near the friction zone were recorded during tests. The applications of the material depend on the wear regimes and mechanisms occurring in the tribocontact. Changes in wear regimes and mechanisms were assessed in terms of differences in the behavior of the friction coefficient and temperature, differences in the condition of friction surfaces and wear rates, and products of wear. The results suggest that hot pressing of powder containing the alloy B83 and discrete particles of the high-strength intermetallic phase Ti₂NbAl is a promising method for producing composite materials with better tribological properties than the babbitt alloy. The introduction of reinforcing high-modulus particles of intermetallic compounds changed the structure of the material and affected the friction processes in the babbitt alloy, delaying the moment when wear regimes shifted into the zone of more severe friction conditions. A substantial reduction in the wear rate of the produced composite materials compared to the initial alloy makes it possible to predict the increase in the service life of tribounits. These data can help determine and recommend the regimes for increasing the service life of tribounits based on B83 alloy as volumetric liners and plain bearings (or sliding bearings), as well as produce new functionally structured layer compositions having enhanced tribological properties, which are based on structural steels and surface coatings using not only B83 babbitt alloy but also its composite materials.