Friction Assisted Joining of titanium and polyetheretherketone (PEEK) sheets. (September 2018) - Lambiase, Francesco
Abstract: Friction Assisted Joining process of titanium and Polyetheretherketone sheets is investigated. Laser texturing was previously performed on the titanium sheets to promote the mechanical joining between the substrates to increase the strength of the joints. Infrared thermography was conducted by means of an IR camera to measure the temperature trend and distribution during the joining process. Quasi-static single lap shear tests were performed to determine the influence of the processing conditions on the strength of the joints. Morphological analysis and fracture surface analysis were conducted to understand the influence of the energy supplied on the quality of the joints. The joints with the highest strength were achieved after the minimum heating time 7.5 s. These joints where characterized by a shear strength of 37.3 MPa corresponding to 66% of that of the PEEK material. Longer heating times resulted in severe thermal degradation (carbonization) of the polymer in the central region, which was due to the low thermal conductivity of the titanium. Nevertheless, the Ultimate Shear Force continuously increased with the heating time up to 8.85 kN (for heating time of 25 s) due to the increase in the joined area. Highlights: Friction spot joining of titanium and PEEK materials has been investigated. The materials did not show chemical affinity, thus laser texturing was performed. Under optimal conditions, an average shear strength of 37 MPa was achieved. Longer heating times produced dramatic degradation of the polymer.