Influence of the notch for mechanical properties of 7020 aluminium alloy jointed by FSW

The article presents the results of the mechanical properties of aluminum alloy AW 7020 [AlZn5Mgl] welded by friction s tir welding FSW. Friction Stir Welding (FSW) - a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. In the article the parameters for friction stir welding of sheets made of AlZn5Mgl [7020] alloy were presented. Analysis of bonds showed a proper structural construction of the FSW welded 7020 aluminum alloy. The test was examined via the slow-strain-rate-testing (SSRT) according to ENISO 7539-7. The following parameters were measured: time-to-failure - T [min], obtained max. load - F [N]; strain energy (the diagram surface under the stress-elongation curve) - E [MJ/m3]; relative elongation of the specimen - A10 [%]; max. tensile stress - R [MPa] and contraction - Z [%]. The tests were carried out on cylindrical notch-free specimens and on specimens with "U"- notch in the air. Despite the use of "U" - notch cut in the joint, the specimens cracked in the native material. On the basis of test results were high strength properties of aluminum alloy 7020joints welded by FSW. Original values are received results of the mechanical properties of new method friction stir welded AW- 7020 [AlZn5Mgl] alloy.