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Graphene, as a reinforcement for composite materials, has become a focus recently. However, the dispersion of graphene in composite materials is a problem that has been difficult to solve for a long time, which makes it difficult to produce and use graphene-reinforced composites on a large scale. Herein, methods to improve the dispersion of graphene and dispersion mechanisms that have been developed in recent years are reviewed, and the advantages and disadvantages of various methods are compared and analyzed. On this basis, the dispersion methods and mechanisms of graphene are prospected, which lays the foundation for graphene application and preparation.

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AbstractNanocarbon materials (carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, etc.) are considered the ideal toughening phase of ceramic matrix composites because of their unique structures and excellent properties. The strengthening and toughening effect of nanocarbon is attributed to several factors, such as their dispersibility in the matrix, interfacial bonding state with the matrix, and structural alteration. In this paper, the development state of nanocarbon-toughened ceramic matrix composites is reviewed based on the preparation methods and basic properties of nanocarbon-reinforced ceramic matrix composites. The assessment is implemented in terms of the influence of the interface bonding condition on the basic properties of ceramic matrix composites and the methods used to improve the interface bonding. Furthermore, the strengthening and toughening mechanisms of nanocarbon-toughened ceramic matrix composites are considered. Moreover, the key problems and perspectives of research work relating to nanocarbon-toughened ceramic matrix composites are highlighted.

High-quality joints between titanium alloys and stainless steels have found applications for nuclear, petrochemical, cryogenic, and aerospace industries due to their relatively low cost, lightweight, high corrosion resistance, and appreciable mechanical properties.is article reviews diffusion bonding between titanium alloys and stainless steels with or without interlayers. For diffusion bonding of a titanium alloy and a stainless steel without an interlayer, the optimized temperature is in the range of 800-950°C for a period of 60-120 min. Sound joint can be obtained, but brittle FeTi and Fe-Cr-Ti phases are formed at the interface. e development process of a joint mainly includes three steps: matching surface closure, growth of brittle intermetallic compounds, and formation of the Kirkendall voids. Growth kinetics of interfacial phases needs further clarification in terms of growth velocity of the reacting layer, moving speed of the phase interface, and the order for a new phase appears. e influence of Cu, Ni (or nickel alloy), and Ag interlayers on the microstructures and mechanical properties of the joints is systematically summarized. e content of FeTi and Fe-Cr-Ti phases at the interface can be declined significantly by the addition of an interlayer. Application of multi-interlayer well prevents the formation of intermetallic phases by forming solid solution at the interface, and parameters can be predicted by using a parabolic diffusion law. e selection of multi-interlayer was done based on two principles: no formation of brittle intermetallic phases and transitional physical properties between titanium alloy and stainless steel.

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