The Study of the Effects Intermetallic Phases Formation on the Bond Strength and Electrical Resistivity of Al/Cu Bimetal produced by Compound Static Casting

In this investigation the Al/Cu bimetals were produced by compound casting method. The effect of aluminum melt pouring temperature and copper preheating on bond strength were assessed. The thickness, microstructure and composition of Al/Cu intermetallic compounds (IMCs) were characterized by optical microscope (OM) and electron probe micro-analyzer (EPMA). The results show that the interface of Al/Cu bimetal consists of α-Al2Cu eutectic structure, a thin layer of Al2Cu and a thin multilayer includes of AlCu, Al3Cu4, Al2Cu3, Al4Cu9. Raising the Al melt pouring temperature and preheating solid Cu leads to increase of the IMCs thickness at interface and consequently increases the specific electrical resistance and decreases the Al/Cu bond strength. The electrical resistance of Al/Cu bimetals were higher compared to theoretical calculation. The samples bond peeling strength were decreased by increasing the thickness of intermetallic compounds layers. It is founded that both curves of bond strength versus IMCs thickness for cold roll welded samples and compound casting samples have similar trends when bond strength is lower than 120 N/cm.v