Stability of periodic microstructure and property change of mesoscopic materials of phase-separation type alloys.

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1.Microstructure changes during annealing of various kinds of bilayr films on SiO_2 substrates were investigated by means of Auger electron spectroscopy, scanning electron microscopy and transmission electron microscopy. The results are as follows :(1) In the as-deposited state of Ag/Ge, Ag/Si, Al/Ge or Al/Si bilayr films, the inner layris amorphous Ge or Si and the outer layr is polycrystalline Ag or Al. Due to annealing, Ge or Si atoms come out and spread on the free surface forming crystalline Ge or Si clusters.(2) Annealing of Fe/Mo bilayr films brings the formation of FeMo intermetallic compound which is not predicted by the equilibrium phase diagram of Fe-Mo.(3) In the as-deposited state of Cu/Ge bilayr film, the inner layr is amorphous Ge and the outer layr is polycrystalline Cu_3Ge. Due to annealing, the inner Ge layr changes to polycrystalline Cu_3Ge and some Ge atoms come out and form crystalline Ge clusters on the free surface.2.A new calculation method for phase decomposition process based on discrete type diffusion equation was proposed, and two dimensional computer simulations were successfully performed for the phase decomposition in Fe-Mo binary alloy systems by utilizing the new method.3.Ageing behavior of coherent particles such as D0_3 or B2 particles in Fe-base alloys and Ti_3Al particles in Ti-base alloys was investigated and the results indicated that not only the particle coarsening but also the hardness decrease is retarded at the later stage of ageing.4.Dissolution and diffusion of hydrogen and deuterium in Ti, alpha-Ti or Ti_3Al were investigated.