A novel seal-flow multi-vortex friction stir lap welding of metal to polymer matrix composites

• Published in: Chinese journal of aeronautics Vol. 37; no. 1; pp. 451 - 462
• Main Authors: NIAN, Shuaiqiang, LI, Mingshen, JI, Shude, HU, Wei, ZHANG, Zhiqing, SUN, Zelin
• Format: Journal Article
• Language: English
• Published: College of Aerospace Engineering,Shenyang Aerospace University,Shenyang 110136,China%State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China 01.01.2024
• Subjects: Friction stir lap welding; Multi-step pin; Material flow; Tensile shear strength; Metal to polymer
• ISSN: 1000-9361
• DOI: 10.1016/j.cja.2023.04.009

The friction stir lap welding(FSLW)of metal to polymer is a challenging work due to the unavoidable polymer overflowing.Facing this problem,a novel seal-flow multi-vortex friction stir lap welding(SM-FSLW)technology based on the subversively-designed multi-step pin was put forward.Choosing 7075 aluminum alloy and short glass fiber-reinforced polyether ether ketone(PEEK)as research subjects,the welding temperature,material flow,formation and tensile shear strength of dissimilar materials lap joint under the SM-FSLW were studied and compared with those under traditional FSLW based on the conical pin.The multi-step pin rather than the conical pin effectively hindered the polymer overflowing due to the formation of vortexes by the step,thereby attaining a joint with a smooth surface.Compared with traditional FSLW,the SM-FSLW obtained the higher welding temperature,the more violent material flow and the larger area with high flow velocity,thereby producing the macro-mechanical and micro-mechanical interlock-ings and then heightening the joint loading capacity.The tensile shear strength of lap joint under SM-FSLW was 27.8％higher than that under traditional FSLW.The SM-FSLW technology using the multi-step pin provides an effective way on obtaining a heterogeneous lap joint of metal to poly-mer with the excellent formation and high strength.