Study of Microdirectional Cu–W Contact Separation Stage Based on Multiphysics Coupling

Abstract

The failure of welding of contact materials is a key factor restricting the improvement of electrical life and reliability of high-power electric contact switch electrical appliances. To study the melting deformation of microscopic contact area during the formation of contact static fusion welding, a new Cu-W composite contact with a 3-D quadrilateral, hexagonal, and rhombic dodecahedral microdirectional skeleton structure is designed. Based on the theory of fluid dynamics, the dynamic formation process of the molten metal bridge in the contact separation stage is numerically simulated; the temperature distribution, contact resistance size, and shape change of the contact surface are analyzed, and the size of the molten pool formed in the contact separation stage of the studied composites with different skeleton structures is calculated. The results show that the highest temperature of the Cu-W composite contacts with microdirectional skeleton structure occurs in the electrical contact position during the formation of molten metal bridge, among which the contact surface temperature of the composites with the rhombic dodecahedral skeleton structure is the lowest, and the contact resistance, liquid bridge deformation, and molten pool volume are the smallest. Both simulation and experiment show that the micro-oriented W skeleton structure can reduce the contact resistance between contacts, thereby reducing the temperature between contacts, reducing the range of erosion of Cu-W composite material contacts, and enhancing the anti-static welding performance, which has reference significance for the design of low-voltage electrical appliances.