Investigations on the fabrication and the characterization of glass/epoxy, carbon/epoxy and hybrid composites used in the reinforcement and the repair of aeronautic structures N. Guermazi ⇑ , N. Haddar, K. Elleuch, H.F. Ayedi Laboratoire Génie des Matériaux et Environnement (LGME), ENIS, B.P.1173-3038, Université de Sfax, Sfax, Tunisia article info Article history: Received 6 August 2013 Accepted 19 November 2013 Available online 28 November 2013 Keywords: Polymer–matrix composites Aging Thermal properties Mechanical properties abstract This paper reports the fabrication and the characterization of glass/epoxy, carbon/epoxy and hybrid lam- inated composites used in the reinforcement and/or the repair of aeronautic structures. These composites were manufactured by the hand lay-up process. Their physical, thermal and mechanical behaviors are discussed in terms of moisture absorption, thermal stability, tensile strength, elastic modulus, flexural strength, flexural modulus and abrasive wear resistance. The impact of hygrothermal aging on the mechanical properties of each composite group has been also investigated. The main results indicated that after water immersion, all composites showed significant moisture absorption especially for glass/epoxy composite. Thermogravimetric analysis showed that the hybrid composite presented the best thermal stability behavior while the glass/epoxy composite the bad behav- ior. The mechanical properties of the carbon/epoxy composites, in the bulk material, were considerably higher than those of the glass/epoxy; the hybrid structure presented intermediate mechanical properties. The same trend was also observed in terms of wear properties. Finally, a deleterious effect on the strength of all composites due to hygrothermal exposure was established. However, carbon/epoxy composites seem to be less susceptible to aging damage after 90 days at 90 °C. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction With advances in science and technology, there is increasing interest in polymer composites, both in scientific research and for engineering applications. In particular, glass and carbon fiber/ epoxy composites are increasingly in demand for structural appli- cations in the aerospace, automotive and marine industries due to their advantageous excellent specific mechanical performance (mechanical properties/density ratio) and design flexibility com- pared with conventional materials [1–6]. However, it is evident from the literature that polymer–matrix composites (PMCs) which used, for example, as aeronautical engineering structures and in other industrial applications may be generally subjected and ex- posed, in its service life, to different environments usually involv- ing humidity, temperature and mechanical stress [2,7]. This may affect essentially the mechanical performance of aircraft composite parts and reduce their lifetime. In this context, this work can be considered as an attempt to give a scientific response to a real industrial problematic proposed by the Tunisian aeronautical society. In fact, the latter aims to con- struct a database about the characteristic of various fabricated composites dealing with repairing and reconstructing aeronautic composite structures. In particular, it is worth to choose the appro- priate composite structure (glass fiber/epoxy, carbon fiber/epoxy, or hybrid structure) for every damaged part which should be repaired. From the literature review, there are many papers focusing on the fabrication of laminated composites using the hand lay-up pro- cesses and their characterization [8–14]. The performance of these composites was largely investigated and discussed in terms of several properties depending essentially on their use conditions. In addition, the composite performance is directly related to the performance of the fiber, the matrix and the interface. Schutte has reported on its work that the durability of glass fiber/polymer composites is dictated by the durability of the components: glass fiber, matrix, and the interface [15]. In fact, environmental attack by moisture, for example, can degrade the strength of the glass fiber; plasticize, swell, or microcrack the resin and degrade the fiber/matrix interface by either chemical or mechanical attack. Many others researchers have used severe and accelerated con- ditions (different environments: water, saline water, acidic water, organic fuel, low and high temperatures) in order to predict the performance of the carbon or glass fiber reinforced polymeric com- posites [7,9–11,13,15–21]. 0261-3069/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.matdes.2013.11.043 ⇑ Corresponding author. Tel.: +216 99 614 199; fax: +216 74 275 595. E-mail address: noamen.guermazi@enis.rnu.tn (N. Guermazi). Materials and Design 56 (2014) 714–724 Contents lists available at ScienceDirect Materials and Design journal homepage: www.elsevier.com/locate/matdes