Influence of the 1% Ti content on microstructure, friction coefficient and contribution to the strengthening mechanisms in the Al20Sn1Cu alloy

Al–Sn alloys are widely used as plain bearings in several engineering applications, particularly in internal combustion engines, where the surface properties are the main properties determining the bearing performance and lifetime. Advanced combustion engines and hybrid systems demand the reduction of wear as well as an increase in loading capacity for plain bearings. Thus, new bearing alloys with improved strength and friction properties have to be developed. For this purpose, Al20Sn1Cu and Al20Sn1Cu1Ti (wt.%) ribbons were produced by single roller melt spinning at low speeds. The ribbons were subsequently bonded by co-rolling with Al with 99.9% purity. Microstructure characterization, hardness and wear tests were used to characterize the ribbons and the co-rolled ribbons. The melt-spun samples show that the microstructures of these alloys are composed of an α-Al matrix and homogeneously distributed β-Sn and γ−Al3Ti. The addition of Ti affects the microstructure by reducing the size of α-Al grains and by changing the distribution and size of Sn particles, resulting in increased hardness and a reduction of the friction coefficient.