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The effects of dissolved carbon in ferrite matrix on the deformation behaviors during the cold rolling were studied in a low carbon steel by the texture measurements and TEM observations. The slip was more inhomogeneous in the specimen with higher dissolved carbon atoms. The specimen in which few carbons were dissolved showed only a few shear bands though at the 80% reduction, otherwise the specimen having a large amount of dissolved carbons showed that the formation of shear bands was one of the deformation mechanisms at the reductions higher than 50%. The crystal rotation to the stable end orientation for the rolling was hindered by the inhomogeneous deformation mechanisms such as shear bands. Thus the lower orientation density in the rolling texture was developed in the specimen with higher dissolved carbon atoms. The preferred formation of shear bands in the｛111｝$lt;112$gt; oreinted grains lowered the｛111｝$lt;112$gt; orientation density in the rolling texture of the specimen with dissolved carbon atoms, of which the development of shear bands was one of the important deformation mechanisms during the deformation.

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Brass electrodeposits were obtained from cyanide baths at 45℃ under current densities from 0.5 to 10.0A/d㎡ and from a sodium tartrate bath at 35℃ under 1 to 20A/d㎡. The cathode current efficiency decreased and the zinc content in the brass deposits increased with increasing current density (overvoltage). The lattice parameter of the electrodeposited α-brass obtained from the cyanide baths increased linearly with increasing zinc content up to about 30% in accordance with equilibrium values, even though additives tended to a little decrease the zinc concentration from which β` started to co-deposit. On the other hand the α lattice parameters of the deposits obtained from the sodium tartrate bath were almost constant up to about 25% Zn due to codeposition of β`. The dezincification of the brass electrodeposits was more influenced by existence of β`phase rather than zinc contents. Theβ`phase thnded to increase tended dezincification.

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The purpose of this study is to investigate the deformation characteristics and microcrack initiation behavior depending on the microstructure of Widmanstatten-α(Wα) and equiaxed-α(Eα) in a Ti-6Al-4V Alloy. In Wα structure, microcracks were observed to form along the α/β interfaces, the colony boundaries and the grain boundary α layers both in tension and fracture tests. In Eα structure, most of microvoids were found to form at the α/β interfaces. The lower tensile strength and ductility of Wα structure was mainly due to the strain localization along the prior β grain boundaries and colony boundaries, which was preceded by the easy slip transfer through α/βinterfaces within the colony. The large increase in fracture toughness of Wα structure was, however, primarily attributed to the crack path deviation depending on the colony orientation.

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The MgO solubility is measured in the CaO-SiO₂- Fe_tO-MnO($gt;8wt%)-MgO-P₂O_5 slag system which is in equilibrium with molten iron in the temperature range of 1550˚C. The Effect of MnO on the MgO solubility and the method for calculating the MgO solubility using slag composition and temperature and discussed, respectively. The amount of MnO content itself has an effect to raise the same amount of Fe_tO content in basic slag. On the other hand, in acidic slag MnO has an effect to raise basicity. Moreover, above results are applied to real low slag operation of 250ton LD converter to study the relationship between MgO solubility and the erosion of MgO-C refractory. The MgO solubility is in the range of 5 to 5.5 wt% at blow end of low slag operation.

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A study on the extraction of In(III) and Ga(III) from sulfuric acid solutions with liquid membrane in the D₂EHPA-Kerosene-Span 80-H₂SO₄, system has been performed and a kinetic model has been proposed. Also the separation of In(III) and Ga(III) from mixed sulfuric acid solutions has been performed. The extraction percentage of In(III) and Ga(III) increased with stirring speeds up to 300r.p. m. and with the decrease of V_(ia)/V_o and V_w/V_e ratios. In the case of Ga(III) the extraction percentage increased as the surfactant concentration decreased. In the model we considered the chemical reaction at the interface between external aqueous phase and emulsion phase, the diffusion through the emulsion phase, breakage and swelling of the emulsion. Results calculated by this model were found to be in good agreement with the experimental data. In mixed solutions, the extraction percentage of In(III) and Ga(III) also increased with the pH of the external aqueous phase. The experimental conditions for optimum separation between In(III) and Ga(III) are as follows:5vol.% D₂EHPA, 3vol.% Span 80, pH=3, 300rpm, V_w/V_e=10 and extraction time=15minutes.

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The Si₃N₄/STS304, Si₃N₄/Cu and Si₃N₄/Si₃N₄, joints was vacuum-brazed with three types of Cu-Ag-Ti braze alloy at 1163 K for 1.6 ks. The microstrusture and microchemistry of reaction products formed at the Si₃N₄/braze alloy interface have been investigated by scanning electron microscope(SEM) equipped with energy-dispersive spectrometer(EDS). The reaction prodsct of Si₃N₄/STS304 joint was a layered structure consisted of nonstoichiometric titanium silicide and iron titanium silicide which was formed by soild-state reaction between titanium silicide and Fe dissolved from the stainless steel. For the joint brazed with Cu-Ag-Ti-Al rather than Cu-Ag-Ti alloy, Cu-Ag-Ti-Sn alloy, thickness of iron titanium silicide layer was decreased and shear strength was increased. The reaction product of Si₃N₄/Cu and Si₃N₄/Si₃N₄joints were a single layer consisted of nonstoichiometric titanium silicide without the formation of the second reaction layer. The former consists of Ti, Si and a small amount of Cu, the latter consists of Ti and Si only. The thickness of those reaction product layer was considerably decreased in comparision with that of the Si₃N₄/STS304 joint(the reaction layer thickness of Si₃N₄/STS304, Si₃N₄/Cu and Si₃N₄/Si₃N₄joint brazed with Cu-Ag-Ti alloy were about 3.50, 0.45 and 0.55㎛ respectively). Also the shear strength of those joints was considerably increased in comparision with that of the Si₃N₄/STS304 joint(the shear strength of Si₃N₄/STS304, Si₃N₄/Cu and Si₃N₄/Si₃N₄joint brazed with Cu-Ag-Ci alloy were average 30, 232, and 256 MPa respectively). Conclusively, whether the second reaction product layer is formed or not depends on the type of adhered metal, and the variation of those thickness depends on the chemical composition of brazing alloy. When the reaction layer is a single layer consisted of nonstoichiometric titanium silicide and the formation of second reaction layer is minimized, high shear strength joints can be obtained.

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