Evaluation of the thermomechanical influence of the joining process (Friction Spot Joining - FSpJ) on the polymeric partners properties of CF-PPS/AA2024-T3 with PPS film interlayer hybrid joints

Abstract

Friction Spot Joining (FSpJ) is a new joining technique developed and patented in 2005 at Helmholtz Zentrum Geesthacht (HZG), a german research center. This joining technique has been investigated into a cooperation between Prof. Leonardo Canto (UFSCar, Brazil) and Prof. Sergio Amancio (HZG, Germany). Hybrid joints of carbon fiber reinforced poly(phenilene sulfide) (PPS) and AA2024-T3 with additional PPS film interlayer were produced at HZG during the beneficiary internship. The present project has as the main goal the evaluation of the thermomechanical influence of the joining process (FSpJ) on the polymeric partners properties of CF-PPS/AA2024-T3 with PPS film interlayer hybrid joints. For this purpose, two polymers characterization techniques were selected: Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Changes on glass transition temperature (Tg) and crystallinity level of the CF-PPS and PPS interlayer on the joints will be evaluated by DSC. In comparison to the base material properties, changes on crystallinity level of polymeric partners must expose the thermal history of the joints in order to clarify the thermal cycles imposed to the materials during the joining process. Thermogravimetric Analysis will identify changes on the onset temperature of mass loss between joined material and base material. Possible degradation of the polymeric partners during the joining process could be identified by changes on the onset temperatures. At the end, the process parameters of FSpJ will be correlated to the changes on the polymeric partners properties, a complete analysis will be carried out through a statistical software.