Welding failure analysis of tungsten-copper composite material used for microwave circuits

Due to have excellent thermal, electrical performance, W-Cu composite materials were wildly used in high-power microwave devices and large-scale integrated circuits as the substrate, embedded blocks, connectors and heat dissipation devices. This paper aiming at the problem of welding failure between a batch of home-made W-Cu composite materials and the Kovar alloy when doing microwave circuit welding. Compared with to the import W-Cu composite materials, scanning electron microscopy (SEM) and electron probe energy dispersive spectroscopy (EDS) were carried out on the microstructure and micro-area composition analysis. The poor welding causes of the materials were found. Through improved technology, increase the Cu content in the Cu-W composite material, and its weld ability with Kovar alloy was enhanced.