Studying of tool rotation speed on mechanical properties of copper-Al5083 butt joint welded by friction stir welding

摘要

In this article, Al5083 and pure copper plates were connected by friction stir welding in butt position. The effects of tool rotation speed on mechanical properties and microstructure of the joint have been investigated experimentally. A joint that was formed at the rotation speed of 800r/min and tool transverse speed of 40mm/min had the highest tensile strength, about 96% of the weak base metal strength. Joint strength at high speeds was due to formation of intermetallic compounds, and it increased the probability of defect formation, and reduced and conversely increased the strength at low rotation speeds by increasing the material mixing and formation of metal matrix composite. Microstructural examination revealed that the intermetallic compounds formed during processing and Al4Cu9 and Al2Cu were detected by X-ray diffraction analysis in the stir zone as intermetallic compounds. Formation of intermetallic compounds increased with increase in the rotation speed. The fracture surface showed that the fracture starts from the interface and brittle failure occurs.