발간논문

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Fabrication of copper clad iron-42% nickel alloy rods or wires (copper ratio : 18-28%) by hot drawing has bean studied laying emphasis on various drawing processes. The processes are composed of predrawing for reduction of clearance between a core rod and a copper tubing, hot drawing for bonding between the core and the copper layer of the predrawn rod, and cold drawing of the composite rod to a predetermined size. The predrawing process was taken for tube sinking or tube drawing with a moving mandrel depending on dimensions of core and tubing and reduction in area. The important factors in hot drawing were the drawing die angle and the clearance between core and tubing. These could be understood by measuring the hardness distribution in cold drawn composite rods.

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With the published data of solubility of hydrogen in Mo and Mo-base alloys, the free energy interaction parameters(ε) of each alloying elements are calculated. These data cover the temperature range from 900 to 1500°K and from the ε vs 1/T (temperature) plot, enthalpy and entropy interaction parameters of each alloying elements are calculated. The two major parts of the effect of alloying elements on the solubility of hydrogen, i.e. the effect of the electronic structure and that of the strain are discussed briefly. And finding is that the former contributes dominantly to the enthalpy interaction parameter and the latter to the entropy interaction parameter. Applying the above findings to the Nb-Ta system, the argument is justified more clearly.

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