Effect of copper-rich precipitations on the adaptive behavior of low carbon martensitic steels during dry sliding wear

Abstract

The adaptive behavior of martensitic steel during sliding wear, such as tribo-oxidation layer (ToL) formed in situ on the wear surface and the plastic deformation layer (PDL) formed spontaneously on the subsurface layer, can effectively inhibit wear. In this paper, the dry sliding wear behavior of 15-5 PH martensitic stainless steel after solution treatment and aging treatments was analyzed, and the influence mechanism of copper-rich precipitations (CPRs) on the adaptive behavior during wear process was explored by molecular dynamics simulation. The results show that the average wear loss of 15-5 PH steel aged at 450 $°C$ is about 89.7 % lower than that solution quenching at 1050 $°C$ under the action of nanoscale copper-rich precipitations (Nano-CPRs). The Nano-CPRs effectively hinder the slip of dislocations, which not only enhances the deformation resistance of the material, but also promotes the formation of more uniform subgrain boundaries in the subsurface. A large number of sub-grain boundaries enhance the overall performance of the PDL that effectively prevent the failure and serious wear of the ToL. This work reveals the failure mechanism of the ToL, the formation mechanism of the PDL and the influence mechanism of the CPRs on friction adaptive behavior of 15-5 PH steel, and also provides theoretical support for optimizing the wear resistance of martensitic steel.