Interfacial examination of Cu/AI joints using ultrafine Al-Si powder as brazing filler metal

摘要

Al-Cu joints have been widely used in electronic and heat exchanger industries due to their excellent electrical and thermal conductivity. Meanwhile, the use of Al in the Al-Cu joints can result in lower weight and cost of the final structure. The purpose of the current study is to join Al to Cu by furnace brazing using ultrafine Al-Si powder. To study the microstructure of the join area, the brazing tests were conducted in the range of 590 to 610°C for 5 to 15 minutes under inert atmosphere. The microstructure of Al/Cu joints was studied by scanning electron microscopy (SEM). The elemental analysis was conducted using an energy dispersive spectrometry (EDS) system. Experimental results show that two kinds of intermetallic compounds (IMCs) mainly Cu_3Al_2 and CuAl_2 phases are formed near the interface of copper and in the braze layer region. The bulky prismatic structure which is formed on the side of Al substrate was found to be a-Al+CuAl_2 eutectic.