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The kinetics of growth of the gamma prime precipitates in Inconel 700 alloy were studied by means of electron microscopy. The coarsening behavior of the gamma prime precipitates was determined as a function of aging time by measuring the particle sizes of samples aged at 760℃, 840℃ and 880℃, respectively. The aging kinetics was shown to be in good agreement with the predictions of the Lifshitz-Wagner theory of diffusion-controlled coarsening at all aging temperatures examined, since the mean particle size increased with the 1/3 power of the aging time. The value of the activation energy for the coarsening process was found from the experimental data to be 60.9 ㎉/㏖.

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The liquid aluminum-zinc and-tellurium systems have been investigated by dew point method for clarifying their thermodynamic properties. In this work, the dew point method has been improved so as to find out the dew point thermoanalytically and record it automatically. Consequently the measuring operation is simpler, and that the result is more accurate than that of ordinary one. The measurements were carried over entire composition range for both systems, and in the temperature range 650° to 800℃ for the Al-Zn system and 770℃ to 920℃ for Al-Te system. The activities of the components Al, Zn and Te of both systems have been derived using the measured data, and also calculated from quasi-chemical approach, regular solution theory and the heat of fusion of Al₂Te₃. The values derived in various ways agree well one another. The interaction energies and shortrange order parameters for the Al-Zn system have been calculated from quasichemical approach and it has been found that the results are reasonable to compare with the classical thermodynamic properties.

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Dispersion strengthening of nickel with zirconium oxide was performed by blending of colloidal zirconia and zirconyl nitrate solution with fine nickel powder. The mixture was baked at 800℃ in reducing atmosphere, pressed, sintered, and reduced over 90%. The results of microstructure and mechanical property tests of the final strips showed a good characteristics of dispersion strengthening of nickel.

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Sodium glass was used as non-metallic base for electroless nickel deposits for the study of interfacial phenomena between glass and nickel. After nickel deposition, the interface of specimen was observed by reflection microscope and electron microscope. The structural change of heat treated specimen was studied by X-ray diffraction method. The adhesion mechanism of metallic layer and base surface might be mainly mechanical phenomena according to the observation from electron micrographs. Strong adhesion was produced by the formation of numerous joints as dove-tails. Furthermore, possible intermediate phase could be presumably proposed as an important role of the adhesion between the two phases.

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80Ni-20Cr electrical resistance heating alloys containing 1.0%∼2.78% Si and 0∼0.2% mischmetal were prepared, and their life cycle, microstructure, electrical resistance and mechanical strength were investigated. Investigating the effects of the added elements on the life of alloys, it was found that the significant improvements were observed as Si contents increase when there exists mischmetal. Effects of mischmetal addition through grain growth inhibition are also discussed.

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The mold properties on the early stage of 2 CaO·SiO₂ self-hardening sand contained 1% of 2 CaO·SiO₂ powder, are investigated according to the molecular ratio of water glass, which are very useful for controlling of molding method and surface in fields. From the results obtained on this study, the following tendency could be found; 1) The higher molecular ratio-water glass seems to be reacted more rapidly with 2 CaO·SiO₂ than the lower does; thus the specimen of the higher appears higher compressive strength during the specimen is held for 15 min. through 7 hrs after molding. 2) The sand mixture might be usable within a definite time after mulling to have enough mold strength for preventing the drops and cracks within 15 min. through 30 min. depend on the molecular ratio. 3) The desirable moisture content, under 2% remained after holding the specimen for 24 hrs, would be shown when the water glasses are added of which molecular ratios are 2.77 through 3.25. 4) Regardless of the molecular ratio of water glass to be added, the longer holding time after ramming the mold, the better mold surface stability can be obtained. however the lower molecular ratio, the better early surface stability is shown.

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Chemical vapor deposition techniques have been applied to refractory metals, ceramics, semiconductors, insulators and conductors. The principles and techniques of chemical vapor deposition reactions for the above materials are reviewed. A new design concept of a high temperature hoop stress measurement apparatus for C.V.D. tungsten and other refractory metal alloys is discussed.

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Superplastic deformation results from a high sensitivity city of the flow stress to the rate of straining so that large uniform elongations may be obtained. A high strain rate sensitivity may be obtained by temperature cycling a metal about an allotropic transformation temperature or by deforming a very fine grained material at temperatures above 0.5 Tm. This latter method offers more scope for industrial application. The low stress and high ductility found with superplastic alloys enables simple vacuum forming techniques to be employed avoiding the necessity of expensive tool materials. This saving in tooling costs can more than offset the increased material costs of superplastic alloys vis-a-vis conventional alloys.

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