Friction Spot Joining of carbon fiber reinforced PPS and AA2024-T3 with PPS film interlayer

Abstract

Friction Spot Joining (FSpJ) is a new joining technique for polymer-metal hybrid structures developed and patented at the research center Helmholtz Zentrum Geesthacht (Germany, 2005). A cooperation between Prof. Leonardo Canto (UFSCar, Brazil) and Prof. Sergio Amancio (HZG, Germany) has been investigating the appliance of this technique with several combinations of materials. The main goal of this project is to evaluate the laminate CF-PPS and AA2024- T3 with PPS film interlayer joints in terms of the effect of the additional film interlayer on the microstructural features, mechanical performance and durability of the joints. The joints were produced at HZG during the beneficiary internship, period also dedicated to joining parameters, surface treatments and film thickness optimization. By optical microscopy, the microstructure and the joints bonding mechanisms will be analyzed. The joints shear strength will be evaluated through lap shear tests in order to face the mechanical performance of joints with and without film interlayer. Additionally, through fatigue and accelerated aging tests, the durability of the joints will be investigated and compared with the traditional joints without interlayer. The failure mechanisms of the joints under static and dynamic loads are going to be evaluated by scanning electron microscopy (SEM). Furthermore, the thermo-mechanical influence of the process on the joints properties will be studied through a correlation between microstructural features and micro/nanohardness in the thermal and thermo-mechanically affected zones. The joints crystallization and degradation have been studied in a cientific initiation project (IC), based on DSC and TGA thermal analysis, conducted with financial support of FAPESP (Jan-Jul/2014) by the beneficiary and will be also used in the present work to understand the thermo-mechanical influence of the process on the joints properties. Finally, it is expected to correlate FSpJ process parameters (rotational speed, plunge depth, joining time and joining pressure), microstructure and mechanical performance of the CF-PPS/PPS/AA2024-T3 joints.