Key Engineering Materials Vol. 814

Abstract: Functionalized graphene oxide (fGO) nanoplates were added to the Poly (trimethylene terephthalate) (PTT) matrix by melt mixing. The mechanical property and deformation mechanism of PTT/fGO nanocomposites were studied. Addition of a small amount of fGO in PTT improves remarkably tensile properties. The elongation break of PTT/fGO increased with addition of fGO in PTT matrix owing to preferential interaction between groups of fGO and PTT matrix.. The fracture mechanism is identified by scanning electron microscopic (SEM) ananlysis of the fracture surfaces. FGO in PTT/fGO nanocomposites were homogenously dispersed in PTT matrix, indicating that the function of fGO improve the compatibility between PTT and fGO.

Abstract: A hydrothermal method using tetrabutyl titanate and KOH as reactants for synthesis of K₂Ti₆O₁₃ nanowires was developed, obtaining nanowires with a uniform diameter around 10nm. It is shown that the hydrothermal temperature and the KOH concentration have little influence in tuning the growth of K₂Ti₆O₁₃ nanowires. By changing the time for hydrothermal reaction, the length of K₂Ti₆O₁₃ nanowires can be controlled from several dozen of nanometers to several hundreds of nanometers. The as-prepared K₂Ti₆O₁₃ nanowires exhibit a wide and strong absorption band in the ultraviolet range (around 200~300 nm), and stable photocurrent of 0.5μA/cm², which might suggest potential applications in solar cell and water splitting.

Abstract: {100}-faceted copper nanostructures with different morphology of nanowires and nanocubes have been prepared by one-pot method. The electroactivity of Cu nanowires and nanocubes was evaluated by degradation of p-nitrophenol. As-prepared copper nanowires exhibit higher catalytic activity for p-nitrophenol degradation than copper nanocubes, and outperform most of Cu catalysts reported in literature. Electrochemical reductive reaction of p-nitrophenol is shown to be kinetically first-order.

Abstract: Potassium tantalates is one kind of important semiconductor with potential applications on photoelectric transformation and photocatalysis. Herein, Au nanoparticles were grown on the surface of two kinds of potassium tantalates, KTaO₃ nanocubes and K₂Ta₂O₆ nanooctahedron, by flexible reducing HAuCl₄, and KTaO₃/Au and K₂Ta₂O₆/Au hetero-nanostructures were formed. Although the Au nanoparticles loading enhances the light absorption, KTaO₃/Au and K₂Ta₂O₆/Au hetero-nanostructures exhibit different photoelectric properties. The difference of photoelectric properties of two kinds of potassium tantalates/Au hetero-structures hint the photoelectric-property enhancement depends on multiple factors.

Abstract: Graphene nanosheets/polyurethane (GNS/PU) was prepared in situ by polymerization technique for the manufacture of PU safety shoes soles. The graphene nanosheets/polyurethane composites were characterized for their mechanical properties, thermal conductivity and abrasion resistance, and comparison is made with those of the neat polyurethane. The microstructural properties of GNS/PU were characterized by SEM. The results show that with the increase of the amount of graphene within the range of weight-percentages analyzed, the tensile strength of the composites gradually increases. The tensile strength of the GNS/PU composites increased to 64.14 MPa with 2 wt% GNS, compared with 55.1 MPa for neat PU. When the graphene sheets reached 2 wt%, the abrasion volume reached 71 mm³. Compared with the pure PU, the wear performance of GNS/PU composites was significantly improved.

Abstract: Poly (trimethylene terephthalate) (PTT)/functionalized graphene oxide (fGO) nanocomposites were prepared by melt compounding. The crystalline morphology and crystallization behavior of PTT/fGO with different amounts of fGO were investigated by differential scanning calorimetry (DSC) and polarizing optical microscope (POM). The results show that the crystallization peak shifts to higher temperature after adding fGO, indicating that fGO have a nucleating effect on PTT. The crystallization temperature of nanocomposites increases with increasing content of fGO. The XRD pattern of PTT/fGO nanocomposites almost no change that indicated the degree of crystallinity of the PTT matrix remained unaffected by the addition of fGO. The nanocomposite revealed integrated Maltese crossed spherulitic morphologies. When adding 1% fGO to the PTT, big-sized PTT spherulites occurred and small-sized PTT spherulites were formed around the big-sized PTT spherulites which indicated that the mechanism of nucleation is changed.

Abstract: Although many problems in aluminium matrix composites have been solved, there are still many difficulties and challenges that need to be solved. In this work, graphene reinforced aluminum matrix composites are prepared by hot isostatic pressing and vacuum sintering. The microstructures of composite powders and composites were studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of different ball milling parameters on the microstructures of composite powders were analyzed. The particle size of graphene coated aluminium composite powder increases with the increase of ball-to-material ratio. With the increase of milling time, graphene was gradually dispersed and coated on the aluminium powder particles, and the aluminium powder particles could be completely coated. with the increase of the speed, the large particles are extruded, sheared and the particles become smaller. The internal micro-deformation characteristics of graphene reinforced aluminium matrix composites were analyzed in detail.

Abstract: With the development of electroluminescence application on display, the traditional structures are very classic and often monopolized by special companies in the world. Nowadays, technologies have developed very quickly so that lots of countries focus on the nanoink and substrate material. In fact, the process of producing various flexo screen display can be applied into the variable sized consumer packages by other conductive and phosphor printing material. In this paper, two different sequences of printing will be introduced to compare the advanced style on new structure design. This study also attempts to show the referable ways on materials to help optimize ways in electroluminescence application.

Abstract: The graphene oxide (GO) was prepared by the Hummers method, and then functionalized by 3-glycidoxypropyltrimethoxysilane. Functionalized graphene oxide (FGO) was characterized by using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TG). The results show that 3-glycidoxypropyltrimethoxysilane reacted with hydroxyl group of graphene oxide. The FGO have a sheet-like structure with wrinkles. The shifts of XRD peaks to low degree for FGO indicate the occurrence of intercalation of 3-glycidoxypropyltrimethoxysilane and as well as increase in the thermal stability.

Abstract: Components of gas turbines must be extremely resistant to high temperatures, high stresses, high-temperature corrosion, and erosive environments. The materials used in these environmental conditions are mainly nickel-based superalloys. In this study, the low-cycle fatigue of the nickel-based superalloy Inconel 792 was examined. The total strain range of a gas turbine between 760 °C and 870 °C was considered as the parameter representing the actual gas turbine operation. In addition, tests were performed using a trapezoidal waveform of the total strain to reflect the operation-stop conditions of a gas turbine with frequent shutdowns. The results of the fatigue test were compared with the Coffin–Manson method and energy method. The fractured surface was analyzed using a scanning electron microscope (SEM).