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The effects of melting temperature and holding time on nucleation behavior of graphite were studied thor gray cast iron and for spheroidal graphite cast iron . As melting temperature and holding time were increased, the starting temperature for graphite-austenite eutectic solidification became lower, and the number of eutectic cell became less for the gray cast iron. For the spheroidal graphite cast iron, the degree of undercooling for the reaction became smaller and the amount of cell increased when holding time was 20 minutes, while, when the holding time was 40 minutes, an opposite trend was observed due to an effect of residual Mg within the molten stock. The effect of melting temperature on the amount of eutectic cell was more significant in the gray cast iron than in the spheroidal graphite cast iron. Dissolution of spheroidal graphite into the iron melt was observed to be more difficult than that of flake graphite.

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The strain-rate cycling test was employed to investigate deformation behavior of solid solution Mo-V and Mo-Nb Alloys at the temperature range of 293-573K. Specimens were prepared by arc melting technique with addition of 0.2wt. %Sc. The activation volume for deformation was found to be less than 50b³(b is the Burger`s vector) and independent of strain below 423k. When temperature was above 423k, the activation volume for deformation increased with strain. Based on experimental results, it is concluded that deformation of the molybdenum alloys studied 423k is controlled by the Peierls-Nabarro mechanism.

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The sheet-type texture is dealt with in this article. Experimental pole figures of a commercial cold-rolled steel sheet and two oriented silicon-steel sheets measured by neutron diffraction are analyzed using the computer programme TXSHTC to examine analytical accuracies and to demonstrate the usefulness of Bunge method for quantitative texture information. Discussions are made on the correction of strong primary extinction observed in (200) pole figure measurement and on the sample amount (i.e., number of grains) required for reproducible ODF determination. From analytical results of the oriented silicon-steel sheet, AISI M-06 POSCO, the dispersion (i.e., FWHM) of the easy magnetization direction is estimated as∼30˚ in the rolling plane and∼13˚ in the RD-ND plane over a bulk sample amount with texture sharpness of J=23.5.

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To investigate the crystallographic deformation characteristic of pure Al under static and cyclic stress at 0.4Tm, the compressive creep tests were performed on single crystal of 99.99% aluminum rod, Irrespective of crystallographic orientation, mostly one slip system is operated at the steady state under the condition of cyclic creep acceleration and the spacing of slip steps of the operating slip system is observed to be narrower in the cyclically crept specimen than that of statically crept one. This result implies that the cyclic creep acceleration is due to the enhanced dislocation climb by the cyclic stressing. The lower value of the activation energy of cyclic creep than that of static creep also supports those results.

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The conditions for the formation of β-silicon carbide whisker by vapor phase reaction in SiCl₄-Cl₂C = CH₂-H₂ system have been investigated. The conversion rate of SiCl₄ into SiC increased with reaction temperature and had been taken maximum value when the range of SiC1₄/Cl₂C = CH₂ mole ratio was from 2.5 to 2.8. The β-silicon carbide whisker can be formed in the range of reaction temperature from 1,100℃ to 1,500℃; SiCl₄/Cl₂C = CH₂ mole ratio, from 0.5 to 8.0,; total flow rate of the reactant gas at 300㎖/min. This whiskers were identified as the 8F type SiC by X-ray diffraction and had the length of 20㎛ or longer.

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Strain bursts were observed frequently during cyclic creep of an Al-1% Mg solid solution alloy at a temperature range of 300-390K. In this temperature range, the cyclic creep acceleration occurred and the material showed serrated yielding during tensile tests. It was considered that the softening by repeated unloading and the dynamic strain aging play important roles in causing the strain bursts of the Al-1% Mg alloy. Studies of dislocation structures utilizing TEM showed that the strain bursts were accompanied by collapse of cell walls. The straits bursts are interpreted by the cyclic softening and the dislocation flood originating from cell walls.

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The effects of copper addition on the microstructure of matrix and fracture toughness value of a ductile cast iron was studied. Addition of copper changed the load vs. C.O.D. curve of the as-cast specimen from the Type-Ⅰ to the Type-Ⅲ. The fracture toughness of the cast iron decreased as the copper content increased; 19% decrease of K_(IC)-value was observed when 2,0% of copper was added. More than 1.0% addition of copper did not show significant further effect on the fracture toughness. Copper addition also caused a transition in the fracture mode from a ductile fashion to brittle one.

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