Dry sliding wear features of an Al-20Sn-5Zn alloy affected by microstructural length scales.

Abstract

Al-Sn-Zn alloys are attractive options for use as wear-resistant materials. While Sn promotes self-lubricating characteristics, Zn strengthens the Al-rich matrix. Conventionally, the manufacturing of these alloys involves casting. However, there is still a paucity of studies that associate the solidification microstructure with the wear resistance of these alloys. Inspired by such considerations, this work aims at investigating the wear behavior of an Al-20Sn-5Zn [wt.%] alloy produced by a directional solidification technique. A set of samples with different microstructure length scales was subjected to ball cratering tests using a normal contact load of 0.25 N and six test times. The results show that the dependence of the wear behavior on the microstructure length scale becomes more expressive for longer sliding distances. It was found that coarser microstructures provide an improved wear resistance. In view of that, a possible spectrum of specific wear rates was determined as a function of the sliding distance, considering different microstructure length scales. Finally, experimental equations are proposed to represent a possible range of wear volume and wear coefficient according to the dendrite arm spacings.