The self-lubricating behavior and evolution mechanisms of the surface microporous friction interface of M50-(Sn-Ag-Cu) material

The friction interface structure has an important influence on the friction behavior of self-lubricating materials. In this paper, M50 material covered with surface micropores filled with Sn-Ag-Cu (MM-S-alloy) was prepared by laser melt deposition. From 25-450 degrees C, the friction test results show that MM-S-alloy exhibits distinguished tribological properties due to the existence of the microporous friction interface. Analysis indicates that Sn-Ag-Cu in surface micropores can dynamically precipitates to the worn surface of MM-S-alloy to achieve a lubricating effect, and the increasing of temperature is beneficial to the dynamic precipitation of Sn-Ag-Cu. The whole friction process can be divided into the initial wear stage, fast wear stage and stable wear stage. At stable wear stage, the friction interface is mainly composed of a lubricant-rich surface lubrication layer and a subsurface load-bearing layer, which greatly improves the material's wear resistance. Especially at 350 degrees C, the surface lubrication layer and subsurface load -bearing layer are most easily formed. (C) 2020 The Author(s). Published by Elsevier B.V.