It was tried to apply aluminium monochloride process, one of the refining methods of aluminium, for the concentration of titanium in Al-Ti alloys of practical use obtained by reducing titanium oxide with aluminium in cryolite bath.
As a prcliminary experiment, the reaction between aluminium chloride and titanium was investigated and it was found that the spongy titanium was always chlorinated at the temperature of 800°C to 1, 200°C, and the aluminium contents in the titanium after the reaction were 15.6% at 1, 050°C and 22.8% at 1, 200°C rcspectiverly.
This main reaction is assumed to be as follows:
(3/2+x)Ti(s)+AlCl₃(g)=Ti_XAl(s)+3/2TiCl₂(g)
From the above results, is is considered to be impossible to produce the Ti-Al alloys with small content of aluminium for practical use by the aluminium monochloride process.

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Measurements of decreases in electric resistance of polycrystalline commercial aluminium and superpure aluminium annealed at various temperatures after deformation at liquid-nitrogen temperature reveal that some form of recovery occurs. The apparent activation energies for these recovery processes are 0.55ev for -80--50°C in commercial and superpure aluminium, 0.75ev for -50-0°C in commercial aluminium and for -50--25°C in superpure aluminium, and 0.4ev for -25-0°C in superpure aluminium. The activation energies are discussed in comparison with the recovery processes of copper.
Measurements of X-ray patterns of polycrystalline commercial aluminium annealed at recrystallization temperature after prior deformation at liquid-nitrogen temperature reveal that there are much more subgrains and finer recrystallized grains than that annealed at recrystallization temperature after prior deformation at room temperature.

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Structure changes during hot rolling process are examined, using 99.30% to 99.58% aluminium and the influence of hot rolled structure upon the recrystallization phenomena after cold rolling are investigated. The results obtained may be summarized as follows: (1) The microstructure obtained during hot rolling is generally not homogeneous. (2) The reduction of hot rolling of at least 70% is required in order to change the cast structure to the wrought structure of recrystallized grain. (3) At the rolling speed of 1m/sec in hot rolling, recrystallized structure is observed after 60% reduction, and until the reduction as high as 90%, the grain of specimens is larger in the outer part than that in the inner part. (4) A comparatively homogeneous structure is obtained by areduction of higher degree, but when the total reduction is too large, the stock becomes again heterogeneous with a fall of temperature, and the hardness in the outer part of specimens becomes higher than that in the inner part. (5) Larger partial reduction of hot rolling gives superior properties to cold rolled sheets and it was found that the size of the grains in the outer layer may become coarser or finer than that in the inner layers according to the hot rolling conditions.

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The present report deals with the investigation of the relation between recrystallized grain size of aluminium sheets and pattern of surface produced by anodic oxidation treatments. The pattern is formed from regular arrangements of second phase impurity particles distributed in the surface of sheets, therofore if specimens have not impurities, or are of homogeneous state by dissolving all impurities i. e. solid solution, any pattern cannot be found on the surface at all.
When those particles are dispersed at random and homogeneously, any pattern can hardly be seen. In thus case, recrystallized grains become finer and more uniform in size with finer and more homogeneous dipsersion of particles.
Moreover, it is found that when specimens are heated at higher temperature, the pattern fades gradually out, soluble impurities being dissolved into solid solution and insoluble impurities coaguating together, but recrystallized grains becoming coarser in size due to grain growth.

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The change of hardness distinctly corresponds to the damping capacity of oscillation, the decrement of the Harbert pendulum, the specific volume change or the changes by X-ray analysis. So the properties represented by the indentation hardness may be considered to have some change in the aging period up to the saturated value, more than the measuring errors for which the change of indentation in the duralumin (17S) is studied regard to the appearance of indentation right after quenching for ten hours.
The duralumin (17S) is quenched in water and depressed by Vickers indentator (load: 5-10kg), the hardness of which is used for the analysis of aging, the surface of depression is traced by the Ogoshi Surface Roughness Tester (contact needle type), and then the change of indentation under each load according to the passage of time is studied.
As a result, it seems that the degree of heaving-up varies widely even in the early stages right after quenching for several hours; some are high and quite close to the indentation, others low and widespread around the indentation.

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This paper deals with the experimental study on the aging of eight sorts of Al-alloy, e. g. 2S, 3S, 52S, 75S, Al-Cu-Sn alloy and so on, by means of specific volume analysis. The specimen of the standard dimension 10×10×20mm, is finished with a 04 emery paper as in the case of preparing the specimen for microscopy, polished with chromium oxide, and then its specific volume (significant figures: five figures) is measured by means of a precision chemical balance. After being kept in 500°C for 30 minutes, the specimens are quenched in water and temper aged for a long time at the prescribed temperature (seven degrees of 20, 80, 120, 150, 180, 200 and 220°C tempering). Then the changes of specific volume are pursued. Furthermore, some interesting results in the change of specific volume were obtained when the quenched specimens were aged in rising temperature.
We add that this research owes its expence to the Grant-in-aid of the Scholarship of the Institute of Light Metal Foundation.

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As the third report of the series of experimental research to improve the heat-resistivity of aluminium alloys by means of addition of a small amount of zirconium, the result obtained from experiments on nine casting alloys listed in Table 1 have been described. Heating test was carried out at 400°C and 500°C respectively up to 100 hours and the softening behavior of the alloys were compared through the measurement of Vickers hardness as seen in Fig. 1, and 2. The effect of zirconium was found to be the most remarkable in No. 1 (Y alloy), No. 2 (hydronarium) and No. 3 (Al-Zn-Mg), all of which, even after the heating of 100 hours at 400°C, can retain the same value as-cast hardness. Slight softening, however, was observed at 500°C when they are heated for 100 hours.
The results of the tensile test carried out at room temperature after the heating of 100 hours at 400°C are listed in Table 2 and the hot tensile test data obtained at 400°C are shown in Table 3. The effect of zirconium has been clearly recognized in some casting alloys as in the case of several wrought alloys described in our previous reports.

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In order to improve quality of the die-cast, it is important to control heat (temperature) together with the design of dies, character of die-casting machine, etc., and we studied the effects of shot number and water cooling on variation of distribution of die-temperature.
A method of qualitative improvement for uniform temperature of cavity might be found and an equation for efficiency of water cooling might be proposed by the measurement of die temperature.

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As the laboratory-scale tungsten electrode argon arc melting furnace, designed by the authors, has been completed in their laboratory, nearly twenty binary zirconium alloys as well as several ternary alloys listed in Table 1 and 2, including zircaloy 2 and 3-B have been melted. They were hot forged at 1000°C and then cold rolled down to 0.2mm thick strips, with an intermediate annealing for 1hr at 700°C except two alloys where the amount of alloying element added was too much to be easily worked.
Mechanical properties; hardness, tensile properties and spring limit value, have been mea- sured, the results of with are summarized in Table 4 and 5. Titanium was found to be the most effective element to enhance strength of zirconium, followed by aluminium, molybdenum and tin among the alloys considered.
Heat treatment response of those alloys, including aging of α-quenched alloys has also been considered, with microscopic observations under polarized light.

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The anodic oxidation of metals has been studied conventionally in aquaous electrolyte at room temperature, but we studied it in salt bath electrolyte at higher temperature of about 300°C.
We have been wondering whether the oxidation rate follows the exponential law or not. but, from the result of our experiment it was found that it followed the law, which had been proposed by Mott and Cabrera¹⁾ from the statistical point of view.
The formula is as follows:
dδ/dt=i=N'νΩexp(-W+qa'F/kT)=N'νΩexp-W/kT exp qa'F/kT
where N' Number of ion per unit arer surface. ν Atomic frequency of vibration. Ω Volume of oxide per metal ion. W Heat of solution of metal ion+activation energy for diffusion. k Boltzmann constant. T Absolute temperature. q Positive charge of metal ion. a Bottom to top distance of potential, barrier. F Potential gradient of oxide film. δ Thickness of oxide. t Time
Conveniently the formula can also be expressed as follows:
i=A exp BF A=N'νΩexp(-W/kT) B=qa'F/kT
Young²⁾ and others supported the Mott's formula but Vermilyea³⁾ proposed another formula from his experiments. i=N'νΩexp-W/kT expαF α_??_F(T)
Our result does not coincide with Vermilyea's formula and the coefficieut B is inversely proportional to the temperature as shown in the following table:

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