Friction Stir Welding (FSW) is a solid-state process which is extensively used to join aluminum sheet structures in a wide variety of industries, including aerospace, automotive, railway, and maritime. This research is focused on the influence of the tool rotational speed on the mechanical properties of friction stir welded 2 mm thick AA1050 aluminum alloys butt joints. Tool rotational speeds from 500rpm to 2000 rpm with a 250rpm step and 1.7mm and 1.8mm plunge depth values were used. Experiments were conducted in a vertical Haas VF2 3 axis CNC milling machine center. Three joint specimens were tested for each case. The tensile properties of the friction stir welded AA1050 aluminum alloys were investigated in the direction perpendicular to the friction stir welding joint. Tensile experiments were conducted using a Schenk Trebel Co. tensile test machine and the Ultimate Tensile Strength, the Young's Modulus and strain were calculated. Results were compared with reference material values. In all cases the calculated values were significantly lower than the equivalent reference material values which is expected due to the fact that the area of the welding joint was lower than the specimen cross sectional area, for the welding conditions employed.

This report presents the development of graphene-based nanocomposite coatings on the fiber reinforced composites to improve the coating resistance against the corrosion and other environmental weathering. Graphene nanoflakes were initially functionalized through a silanization process, and then dispersed well into the polyurethane primer and top coats at 0, 2, 4 and 8wt% using high speed agitation and sonication processes. The dispersed nanocomposite coatings were an air sprayed on the surfaces of the composite coupons at different thicknesses, and cured prior to the alternative UV and salt fog exposure tests for 20 days. The performance analyses of the nanocomposite coatings were carried out using atomic force microscopy (AFM), Fourier transform infrared spectrometer (FTIR), thickness measurements, water contact angle, and electro-chemical impedance spectroscopy tests. The test results indicated that the silanization process on the graphene nanoflakes significantly improved the corrosion resistances of the nanocomposite coatings when compared to the non-functionalized graphenes. This study may be useful for the performance improvements of many coatings on the composite aircraft, wind turbines and other applications.