Optimizing the friction behavior of medium entropy alloy via controllable coherent nanoprecipitation

Abstract

In recent years, FeCrNi medium entropy alloy, a new material with high hardness, strength, ductility, and wear resistance, has been widely studied. In this work, the effect of precipitation volume fraction on the friction behavior of FeCrNi is studied by molecular dynamics simulation. With the increase of precipitation volume fraction, the average friction coefficient shows an upward trend. When the volume fraction of precipitation is between 2.33% and 3.10%, the wear resistance of FeCrNi would be enhanced after the nanoscratching, and the normal force is large, which means that a certain precipitation volume fraction strengthens FeCrNi. Low precipitation volume fraction can effectively reduce the wear volume and wear rate during scratching, thus effectively lowering frictional force and friction coefficient. The interaction between dislocation and precipitation is an important factor that hinders dislocation propagation, leading to the strong dislocation strengthening and the increase of wear volume. This trend is manifested as the increase of normal force and frictional force. The frictional properties of FeCrNi can be optimized with a certain precipitation volume fraction. The findings give a guiding significance for the effect of multiple precipitation on frictional properties of FeCrNi.