_??_ie Woodsche Legierung wurde während des Erstarungsvorganges der Einwirkung starker Ultraschallwelien der Frequenz 450kHz ausgesetzt. Auffallende Koruverfeinerung, Gleichmachung der KorngröBe und .die Verkürzung der Nadein warden. beobachtet. Dabei war zu bemerken, daB these Wirkungen dann nur in unbedeutendem MaBe auftreten, wenn die Beschallung der Metallschmelze vor dem Beginn der Erstarrung unterbrochen wird.

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Since M. G. Corson invented the age-hardening Cu-Ni₂Si alloy, this alloy has become the most important material for the high strength conductor. The economy of Nickel, however, in all alloys is an urgent problem from the view-point of metallic resource now a days. According to this demand, the experiments of this direction are being carried out at various labor atories. We investigated the age-hardening of copper alloys containing iron Compounds to replace the above Corson-Alloy. First of all, we measured the change of mechanical, physical and chemical properties of copper rich Cu-FeSi, Cu-FeSb, Cu-Fe₂P and Cu-Fe₂As Systems tempered at 100_??_600° 1 hr after, quenching from 900° 1 hr. Secondly, we determined a proper heat-treatment method and optimum ratio of iron and phosphor constituents by equi-hardness curves and egui-conductivity curves in. copper corner of the more useful Cu-Fe-P System. And then we analyzed the age-hardening process of the most interesting Cu-Fe₂P System by mechanical, physical and chemical changes measured on the constant-speed heating after solution-treatment. As consequence of these researches, it is explained that Cu-Fe₂P alloy possesses not only the normal agc-hardening characteristics, but also is a precipitation-hardening alloy such as common ageing copper alloys. And the age-hardening process is performed as follows; (1) Room temperature-150° is the preparation-process for the 1 st precipitation (super-saturated solid solution range). (2) 150_??_250°, the 1 st precipitation hardening process. (3) 250_??_350°, latent process of ageing. (4) 350_??_450°, preparation-process for the 2 nd precipitation hardening, (5) 450_??_600°, the 2 nd precipitation hardening process. (6) over 600°, coagulation or redissolution of precipitants and reduction to stable solid solution.
Futhermore, the electrical conductivity of this alloy is so increased by tempering, that it is proper to apply it to the electrical conductor.

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A-Study on the Refining of Bath Aluminium. (2 nd Report). In order to improve the properties of the bath-aluminium by remelting, the effects of holding, puddling, air-bubbling and nitrogen-treatment of the melt have been investigated, and it is found that the last treatment is, most effective; the aluminium thus treated shows the highest impact value.

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The present author has sometimes reported on the peculiar mechanical properties of extruded. Aluminium alloys. From these experiment reported here it is concluded that the pecurialities are mainly caused from the fibre structure of extruded materials. It will be inferred also that this fibre structure, which extruded materials possess, is produced in the stage of hot working among the extruding process, and can not of be distinguished by the solution heat-treatment. If another deformation process, such as forging or rolling, is applied, the recrystallization temperature is lowered, and then the cxcellent properties disappear by the solution heat-treatment.
This inference on the relation between the peculiar properties and the fibre structure is reinforced by the knowledge of the relation between the mechanical properties and the orientation of crystal observed by Karnop.and Sachs.

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