Investigation of post weld cryogenic treatment on weld strength in friction stir welded dissimilar aluminium alloys AA2014-T651 and AA7075-T651

The main motive of this study was to investigate the feasibility of fabricating aerospace aluminium alloys AA2014-T651 and AA7075-T651 using friction stir welding technique. Both these alloys are difficult to weld with fusion welding processes. Specifically, this study examines the behavior of butt welded 6.35 mm thick plates with AA 2014 plate on advancing side and an AA 7075 plate on retreating side. Joints are fabricated using three different tool materials (HSS, H13 and SS) at varied rotational speeds (900, 1200, 1500 rpm) and welding speeds (40, 60 and 80 mm/min). Taguchi's L9 orthogonal array was used for design of experiments. Tool material was found to be the most dominating factor in establishing the tensile strength. Post weld cryogenic treatment of weld specimens resulted in marginal improvement in mechanical properties of joints. The results of tensile strength have been modeled using artificial neural network (ANN) approach. (c) 2017 Elsevier Ltd. All rights reserved.