Effect of Zn additions on the microstructure and mechanical properties of Sn-Babbitt alloys fabricated by arc deposition

Abstract

A deposited layer of Sn-based Babbitt alloys was fabricated on the surface of the steel substrate via the arc deposition technique. The effect of the composition of Zn on the microstructure and mechanical properties has been systematically studied. The morphology of Babbitt alloys and the interfacial microstructure of the interface between the cladding layer and substrate have been investigated. The experimental results revealed that SnSb phases and Cu6Sn5 phases become more uniformly dispersed in the Sn-matrix as Zn composition increased, which resulting in the improvement of hardness and tensile strength. The enhanced performance can be attributed to precipitation strengthening of the newly formed substitutional solid solution Cu6Zn0.5Sn4.5. The bonding strength of Babbitt and steel has been tested according to the standard destructive testing method of sliding bearing. The bonding strength increased and decreased with the increment of Zn, since excessive Zn led the fracture site to shift from the SnSb phase to the segregated Cu6Sn4.5Zn 0.5 at the interface near IMC layers.