基于Ag-45CuO (骨架Ag-CuO)和Ag-20CuO (岛状Ag-CuO)触点材料的微观结构特征,利用物相识别结合显微结构分析重建了Ag-CuO材料的三维尺度模型,采用计算流体动力学(CFD)方法模拟了侵蚀作用下CuO微观结构的动态演变和重构过程。实验和模拟结果表明,反复的热冲击导致岛状Ag-CuO熔池表面形成火山口状凹坑,而骨架Ag-CuO熔池表面较为光滑。这是由于骨架Ag-CuO触点局部间隙作为CuO骨架重构的驱动力,可使重构后的CuO呈现出更明显的各向异性,从而有效束缚熔池中Ag的蒸发与偏析；而岛状Ag-CuO触点开断过程并未发生明显的CuO重构现象,其基体内岛状CuO结构易使触点在反复侵蚀作用下失效。随后,利用视觉识别技术结合有限元法,逆向重建了骨架Ag-CuO和岛状Ag-CuO触点表层局部的三维模型,进一步研究了CuO微观结构对触点表层力学性能的影响。结果表明,相比于岛状CuO结构,骨架CuO结构的相界面处不易产生应力和应变集中,该结构可有效分散熔池表面局部冲击力,显著提高触点的抗侵蚀性能。

Silver-copper oxide (Ag-CuO) materials are gaining more and more interest in the low voltage switches' field owing to their lower material transfer characteristics. However, with increasing arc erosion during the make-and-break operations, the CuO microstructure's dynamic evolution is complicated by the interaction of the convection-diffusion with the flow path. Therefore, tuning the microstructure to maximize the arc erosion properties of Ag-CuO contact materials using the dynamic model is crucial for their application in switches. In this study, three-dimensional models of Ag-CuO contacts were reconstructed by phase identification and microstructure analysis, using the microstructure characteristics of the Ag-45CuO (skeleton-restricted Ag-CuO) and Ag-20CuO (island-restricted Ag-CuO) contact materials. In parallel, the arc erosion dynamics of the microstructure evolution and skeleton reconstruction process were tracked and explored by employing computational fluid dynamics simulations. Experiment and simulation findings both indicate that the repetitive thermal effect can cause the formation of a cratered and smooth molten pool surface in island-restricted Ag-CuO and skeleton-restricted Ag-CuO, respectively. The local gap of skeleton-restricted Ag-CuO contact can function as the driving force to reconstruct the CuO skeleton, the newly formed CuO with an anisotropic microstructure, which can impede Ag's segregation and evaporation in the molten pool. The restructures of CuO are unimportant for the island-restricted Ag-CuO contact, and the continuous erosion impact of island CuO can render the contact invalid. Additionally, the CuO microstructure's effect on the mechanical properties of Ag-CuO contacts was examined by employing the local three-dimensional models, which were reconstructed using the visual recognition technology combined with the finite element approach. The findings exhibit that the skeleton CuO structure was less susceptible to stress and strain concentration at the molten pool surface compared with the island CuO structure, which can efficiently disperse the local effect force on the molten pool and can substantially enhance the Ag-CuO contact's erosion resistance.