High temperature tribological behaviors of Co-based superalloy Haynes 188

Abstract

In this work, tribological behaviors of solution strengthening Co-based superalloy HA188 were investigated at 900℃, 1000℃ and 1100℃. Si₃N₄ and HA188 were chosen as the counterpart respectively to evaluate the influence of counterpart materials on the sliding wear behaviors. It was found that the formation and destruction of tribo-layer are the dominating factor in the high temperature wear process. The composition and structure of tribo-layer are controlled by oxidation products of HA188 at different temperature. Tribo-layers are composed of NiCoCr-spinels at 900℃ and 1000℃. However, at 1100℃, the tribo-layer composition transfers to Cr₂O₃, which is attributed to the substantial diffusion of Cr to the surface. Moreover, counterpart materials affect the homogeneity and compactness of the tribo-layers. Harder counterparts generate greater stress and deformation in tribo-layer and HA188 substrate, leading to the failure of the tribo-layer and the increase in wear rate.