Microstructures and Properties of Functionally Gradient Materials

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1.The functionally gradient materials (FMG) of the surface coating.(1) The structure and interface of TiC/SiC films coated on C/C composite materials were investigated by TEM,EPMA and X-ray diffraction. Strong preferred orientation exists in these layrs by the epitaxial growth.(2) The difference of bonding of TiC films on cemented carbides, WC,fabricated by PVD and CVD processes were clearly observed with the acoustic microscopy of Vickers indentations and cracks initiated from them by the SEM fractography.2.From the viewpoint of the improvement of materials property degradation at the surface layr by the formation of FGM layr, in the later half of the present reseach project, reseach work was concentrated to the surface structure of finished by ultra-fine polishing.(1) The crystal anisotropy for polishing was investigated. The direct observation of the amorphous layr on a ferrite single crystal was succeeded with the TEM.The depth of surface layr of a single crystal ferrite introduced by polishing was estimated about -3mum.(2) The structures of surface layr, such as the amorphous layr, poly crystalline layr and dislocation structures, were analyzed for polished single crystals of ferrite with various orientation.(3) The presently obtained results suggest that the effects from the surface layrs depending on crystal anisotropy, which may be undesireble for the most effective utilization of materials property, may be eliminated by covering the damaged surface with a FGM layr.