The Anti-Arc Corrosion Performance of CuCr Alloys at Different Micro–Nano Scales Based on Magnetohydrodynamics (MHD) and Equivalent Heat Capacity Method

This article presents a numerical investigation on the arc erosion resistance of three types of CuCr structures: a conventional disordered alloy (A), a surface-nanostructured alloy (B), and a micrometer-scale layered composite (C), with a focus on their interaction with arc plasma under high-voltage conditions. Coupled magnetohydrodynamic (MHD) simulations are utilized to analyze multiphysics behavior in the arc zone, encompassing electromagnetic fields, fluid flow, heat transfer, and molten pool dynamics. The results show that Structure B attains the highest critical breakdown field strength of$0.58\times 106$V/m, which is 41% greater than that of Structure A, indicating superior dielectric strength and arc erosion resistance. The self-induced magnetic field in the arc plasma and the resulting Lorentz force are found to significantly affect plasma flow patterns. Structure B exhibits the lowest magnetic flux density, which contributes to a higher plasma flow velocity—12.7% greater than that of Structure A—and enhances convective cooling, thereby reducing thermal accumulation. Consequently, Structure B achieves the lowest surface heat flux and the smallest ablation depth, measuring 0.13 mm, which is 48% less than that of Structure A. Meanwhile, the ablation depth of Structure C is 0.17 mm, which is 32% less than that of Structure A. Structure C demonstrates intermediate performance, which is attributed to its anisotropic thermal conductivity that restrains vertical energy dissipation. These findings highlight the critical role of micro–nano structural design in regulating arc plasma dynamics and provide valuable insights for the development of advanced contact materials for plasma-facing applications.