investigating on mechanical and microstructural properties of dissimilar aluminum-copper joints fabricated via underwater friction stir welding

In this research, the effects of the water cooling environment on the possibility of al 1050 and pure copper dissimilar joints fabricated by the fsw process underwater with rotation speeds of 800, 1000, and 1250 rpm and constant traverse speed of 50 mm/min were investigated. the welds were discussed in terms of microstructure and mechanical properties. hardness tests were performed along the thickness from the middle of the sample and the maximum hardness of 108.8 vickers was obtained in the copper base metal part in the sample with a rotation speed of 800 rpm. the microstructure of different welding zones and imcs formed by om and sem were observed. the results showed that the highest joint strength is obtained at a rotational speed of 1250 rpm in the water cooling environment at a rate of 2670 n. in the joint interface, mainly al2cu and alcu intermetallic compounds were found. also, in this research, it was found that the size of the haz zone and grain growth in the joint were significantly limited by applying cooling medium.