This thesis aims to fabricate the high performance Magnesium/Carbon-Fiber/PEEK five-layer hybrid nanocomposite laminates. The adopted Mg thin sheets are 0.5mm thick. The Carbon-Fiber/PEEK prepregs were stacked into two lay-ups, such as cross-ply [0/90]s and quasi-isotropic [0/45/90/-45], with the adding of nanoparticles SiO2 spreaded among the laminates. After etching of Mg foils by CrO3-base etchants, a five-layered Mg/Carbon-Fiber/PEEK nanocomposite laminate was made according to the modified diaphragm curing process. Then, the mechanical properties, such as stress-strain curve, strength and stiffness were obtained by tensile test at room temperature (25¢J), 50, 75, 100, 125 and 150¢J and the fatigue properties were also obtained under constant stress amplitude tension-tension cyclic loading elevated at room and elevated temperatures 25, 75, 100, 125 and 150¢J. Finally, the Mg sheets and fractured laminates were observed by the SEM and OM. The results according to the experiments were summarized as follows: 1.The slope of stress-strain curve dropped at strain¡Ü0.0015. It can be inferred that fracture occurred in the laminates at this time. Stiffness approached the theoretical value by curve fitting with the strain range of 0 to 0.0015. 2.The mechanical properties decreased with the environmental temperature rise. 3.The resistance to the temperature effect of the quasi-isotropic Magnesium/Carbon-Fiber/PEEK laminate is superior to that of the cross-ply Magnesium/Carbon-Fiber/PEEK laminate. 4.The cross-ply Magnesium/Carbon-Fiber/PEEK laminate is brittler than that of the quasi-isotropic laminate generally. 5.The irregular bright lines were found in the third etched Mg sheet and that resulted in the delamination of Mg sheet after treatment. The unetched part maybe the defect of Mg sheet. 6. It was found that AZ31 has the precipitation hardening effect at 50¢J and 75¢J.

The purpose of thesis aims to investigate the mechanical behavior and properties of a centrally notched hybrid Al alloy/Carbon-Fiber/PEEK(APC-2) laminate at elevated temperature. The high performance hybrid composite laminates of 0.5mm Aluminum alloy sheets sandwiched by APC-2 cross-ply and guasi-isotropic laminates were fabricated. The prepregs of APC-2 were stacked into cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] laminates spread uniformly with nanoparticles SiO2. The sheet surface was treated by chromic acid anodic method to achieve perfectly bonding with matrix PEEK. The modified diaphragm curing process was adopted to fabricate Al/APC-2 hybrid nanocomposite laminates. The panels were cut into the specimens and then drilled an diameter hole in the center with diameters of 1,2,4,6 mm. The MTS 810 material testing machine was used to conduct the tension and fatigue tests. In addition, the MTS 651 environmental chamber was installed to control and keep the specific testing temperatures, such as ,25¢XC(RT), 75¢XC, 100¢XC, 125¢XC and 150¢XC. At first, the nominal stress(£mnom) and stress-strain diagram were obtained due to static tension tests at elevated temperature. The constant stress amplitude tension-tension cyclic tests were carried out by using load-control mode at a sinusoidal loading with frequency of 5Hz and stress ratio R=0.1. The received fatigue data were plotted in normalized S-N curves at variously elevated temperature. For the tensile tests, at the same temperature the nominal stress of cross-ply specimens was higher than that of quasi-isotropic specimens. Comparing with the notched and unnotched of cross-ply specimens, the nominal stress of notched specimens was about 60% to 80% that of unnotched specimens. Besides, as for the notched and unnotched quasi-isotropic specimens, the nominal stress of notched specimens was about 75% to 85% that of unnotched specimens. Then, the fatigue life and stress-cycles (S-N) curves of notched specimens were obtained often tension-tension fatigue tests. In the case of the same loading, notched specimens possess worse fatigue behavior, but in the same normalized stress ratio, the S-N curves of the unnotched were below the notched ones. The fatigue resistance of notched samples decrease as the temperature rising.

The aims of this thesis are fabrication of Ti/APC-2 hybrid nanocomposite laminates and investigation of their mechanical properties at elevated temperature. The prepregs of APC-2 were stacked into cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] laminates spread uniformly with nanoparticles SiO2. The sheet surface was treated by chromic acid anodic method to achieve perfectly bonding with matrix PEEK. The prepregs were sandwiched with the Ti alloy sheets. The modified diaphragm curing process was adopted to produce Ti/APC-2 hybrid nanocomposite laminates. The nanocomposite laminates were a five-layer composite with two 0.55 mm thick APC-2 layers sandwiched by three 0.5 mm thick Gr.1 titanium alloy sheets. The MTS 810 material testing machine was used to conduct the tension and fatigue tests. In addition, the MTS 651 environmental chamber was installed to control and keep the experimental temperature, such as 25¢XC, 75¢XC, 100¢XC, 125¢XC and 150¢XC. The mechanical proper¬ties, such as ultimate tensile strength, longitudinal stiffness of cross-ply and quasi-isotropic nanocomposite laminates, were obtained from the static tensile test. The stress-strain diagrams were plotted in the corresponding temperature. The constant stress amplitude tension-tension cyclic tests were carried out by using load-control mode at a sinusoidal loading with frequency of 5Hz and stress ratio R=0.1. The received fatigue data were plotted in normalized S-N curves at variously elevated temperature. From the summarized results, some conclusions were made. First, the ultimate strength of Ti/APC-2 nanocomposits was better than Ti/APC-2 composites at room temperature; Second, Both two type nanocomposite laminates¡¦ ultimate strength and S-N curves go downwards as temperature rising, especially at 150¢XC; Third, The fatigue tensile strength of both hybrid composite laminates was the lowest at 150¢XC. Fourth, Ti/APC-2 quasi-isotropic nanocomposite laminates had better fatigue resistance than Ti/APC-2 cross-ply nanocomposite laminates. Finally,The longitudinal stiffness was in good agreement with prediction by using the modified ROM because of the changed curve fitting ranges.

The aims of this thesis to investigate the two step loading of Ti/APC-2 hybrid nanocomposite laminates and their notched effect. Ti/APC-2 laminates were composed of three layers of titanium sheets and two layers of APC-2. Nanoparticles SiO2 were dispersed uniformly on the interfaces of APC-2 with the optimal amount of 1 wt %. Then, APC-2 was stacked according to cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] sequences. The modified diaphragm curing process was adopted to fabricate the hybrid panels for minimal impact of production. The panels were cur into samples and drilled an diameter hole in the center with diameters of 4 or 6 mm. Both tension and fatigue tests were carried out with MTS 810 universal testing machine at room temperature. Also, two-step loading tests include high¡÷low and low¡÷high tests, were conducted. 0.9£mnom is denoted as high load and 0.7£mnom low load for two-step loading spectrum. In both high¡÷low and low¡÷high step loadings the first step is to do cyclic tests at a half life of the corresponding load, and then finish it due to last step load. From the received results, some conclusions were made. First, the ultimate load of notched cross-ply samples was reduced about 50% and the notched quasi-isotropic samples reduced about 30% compared to their unnotched counterparts. Second, the S-N curves are very close for both centrally notched samples of diameters 4 mm and 6 mm in cross-ply and quasi-isotropic samples. Third, quasi-isotropic samples had higher average values of cumulative damage than cross-ply samples. Because of notched effect centrally notched samples of diameters 4 mm had higher average values of cumulative damage than centrally notched samples of diameters 6 mm.

The thesis is to fabricate Al/APC-2 hybrid nanocomposite laminates and investigate their mechanical properties at elevated temperature. The prepregs of Carbon /PEEK were stacked into cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] laminates spread uniformly with nanoparticles SiO2. The sheet surface was treated by chromic acid anodic method to achieve perfectly bonding with matrix PEEK. The prepregs were sandwiched with the Al alloy sheets. The modified diaphragm curing process was adopted to produce Al/APC-2 hybrid nanocomposite laminates. The hybrid nanocomposite laminates were a five-layer composite with two 0.55 mm thick Carbon/PEEK layers sandwiched by three 0.5 mm thick 2024-T3 Aluminum alloy sheets. The MTS 810 material testing machine was used to conduct the tension and fatigue tests. In addition, the MTS 651 environmental chamber was installed to control and keep the specific testing temperature, which was room temperature, 75¢XC, 100¢XC, 125¢XC and 150¢XC. The mechanical proper¬ties, such as ultimate tensile strength and longitudinal stiffness of hybrid cross-ply and quasi-isotropic nanocomposite laminates, were obtained from the static tensile test, and the stress-strain diagrams were plotted in the corresponding temperature. The constant stress amplitude tension-tension cyclic tests were carried out by using load-control mode at a sinusoidal loading with frequency of 5Hz and stress ratio R=0.1. The received fatigue data were plotted in normalized S-N curves at variously elevated temperature. In order to observe the failure mechanism of samples, the scanning electron microscope was used. From the summarized results, some conclusions were made. First, the slope changed at strain=0.1% in the stress-strain diagram, and led to a noticeable error between the experimental data and ones calculated according to Rule of Mixtures. Second, the Al/APC-2 cross-ply nanocomposite laminates were less resistant to fatigue than quasi-isotropic. Third, the ultimate tensile strength of both hybrid composite laminates was the lowest at 150¢XC. Fourth, the Al/APC-2 quasi-isotropic nanocomposite laminates were more resistant to the temperature effect. Finally, The mechanical proper¬ties were better for the surface treated by chromic acid anodic method than chemical etching.