Experimental investigation of carbon long fiber reinforced polyamide 6 exposed to environmental conditions

To enhance the possibilities in lightweight constructions in terms of processability and recyclability, fiber reinforced thermoplastics are a promising class of materials. In this context, the fiber-matrix interface has a major influence on the mechanical properties of the composite. With polyamide 6 (PA6) being a hygroscopic thermoplastic, the effects of elevated humidity and temperature on the mechanical behavior must be considered [1]. This study aims to characterize the micro-mechanical material properties of carbon long fiber reinforced PA6 in quasi-static tensile tests after exposure to elevated temperature and humidity levels. Therefore, the specimens are conditioned in different climates and tested afterwards. In order to determine the initiation and propagation of matrix cracks, interface failure, and fiber fracture, the experiments are conducted on a micro-scale with an average cross-section of 0.03 mm2. The damage patterns are captured using optical microscopy and SEM images. The effects of conditioning at various temperature and humidity levels are discussed. The main results are the qualitative description of the degradation of mechanical properties due to hydrothermal effects.