Research On High Frequency Magnetic Field Induction Welding Of CF/PEEK Composites And Its Failure Mechanism

Carbon fiber/polyether ether ketone(CF/PEEK)composites have become one of the most potential materials due to their excellent specific strength and stiffness,and they are widely used in many fields.With the diversification of application situations,how to ensure the efficiency and reliability of CF/PEEK composites component connection is the focus of current research studies.Induction welding is a fast,reliable,non-contact joining method that can be applied to a variety of complex shapes and is of great importance for joining CF/PEEK composite components.In this paper,high-frequency magnetic field induction welding technology is studied with CF/PEEK composite laminates.Developed a continuous stainless steel fiber/(FeNi/PEEK)composite(FNP)specifically for induction heating,and successfully applied high-frequency magnetic field induction welding to CF/PEEK composite laminates by using FNP.The mechanical properties,microstructure morphology and failure fracture of the welded area were analyzed.The induction welding optimum welding process parameters were obtained,the failure mechanism of the welded zone and the evolution of the mechanical properties of the welded zone with the change of welding process parameters were studied.CF/PEEK composite laminates were made by hot pressing molding process,and the hot pressing process parameters of the laminates were optimized.The tensile strength of the CF/PEEK composite laminate reached 719.00 MPa when the hot pressing temperature was 350 °C,the hot pressing pressure was 2.5 MPa,and the holding time was 10 min.The high-frequency magnetic field induction welding process of CF/PEEK composite laminates was studied,as well as the effects of welding process parameters and FeNi powder content on the mechanical properties of the welded zone.When the FeNi content of 50%,welding power of 2.0 KW,welding time of 80 s,welding pressure of 0.5 MPa,the single lap shear strength of the welded area reached 17.72 MPa.When the FeNi content of 40%,the bending strength of the welded area reached 23.36 MPa.defects in the welded area are mainly due to the welding process caused by leakage areas and due to FeNi nanopowders.The powder deflection defects caused by agglomeration.Adjustment of the welding process can eliminate or reduce the leakage zone,and optimization of the FNP preparation process can make the FeNi powder dispersed uniformly to avoid the defects caused by powder agglomeration.The failure forms of the weld zone are mainly interface failure and interlaminar failure,and the failure forms of the weld zone are closely related to the welding process parameters.When the interface of the weld zone is tightly bonded,the failure form is mainly due to FNP damage and interlaminar failure caused by the breakage and pullout of carbon fibers in the CF/PEEK composite laminate,in this form of failure,the weld zone has a high shear strength.