Revealing the crucial role of skeleton restructuring on erosion dispersion of Ag–CuO contact materials

Abstract

Predicting the second-phase microstructure that evolve in arc erosion processes remains an important challenge in Ag–CuO contacts. In this study, phase identification and microstructure analysis were utilized to reconstruct a 3D model of an Ag–CuO contact for tracking and exploring the dynamic erosion of its microstructures. The results show that the dynamic evolution of the molten pool was strongly affected by repetitive thermal impacts. Ag flow and evaporation in the molten pool provide the driving force for CuO skeleton restructuring, which increased the tortuosity of the flow paths and extended the flow channel length. Thus, molten bridges with large quantities, short lengths, and small diameters were dispersed, thereby improving the surface erosion resistance. Furthermore, the effect of CuO on the micromechanical characteristics of the Ag–CuO contact was examined by employing local 3D models reconstructed using visual recognition technology combined with the finite element method. The findings show that CuO skeleton restructuring efficiently dispersed the local stress and strain concentrations on the molten pool, which delayed contact failure. Therefore, our work confirmed the role of CuO skeleton restructuring in dispersing molten bridges, and relieving stress and strain concentrations in Ag–CuO contacts, thereby further augmenting our understanding of erosion dispersion.