A sigle crystal of high purity aluminium was made by means of soft mold method, which was rolled on the (110) plane and in the [112] direction. After rolling, surface layers and edges were electrolytically etched off and side of the specimen was scrubbed with emery paper to produce random artificial nucleation. Then the specimen was annealed at 350°C for 600sec. A large number of grains were formed on the scrubbed side and some of these grew across the thickness of the specimen. Orientations of grain were checked by X-ray and microscope on the scrubbed side and also on the unscrubbed side. It was observed that grains on the scrubbed side had rather equiaxial shape and random orientations. On the unscrubbed side, however, grains had elongated shape in two directions. These two directions were related to the matrix by a rotation around ‹111› axes. The fact that four of eight equivalent ‹111› rotational relationships were predominant in the grain growth, suggests that the deformed single crystal matrix is not fully symmetrical for the growth rates of recrystallized grains as in the crystallo graphic meaning. It is suggested that the growth rates of recrystallized grains would be affected by the mechanism of deformation of matrix.

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It has been evidently observed by X-ray technique that the grains of aluminium or Al-Cu alloy is, at the begining of extrusion, disintegrated into many small domains with small difference in orientations.
To determine these domains under microscope, several electrolytes were investigated and some favourable conditions were found.
These conditions and polishing method for microstructural test are illustrated with photographs in this paper.

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In order to confirm the effect of Mn and Cr in Al-3-5%/Mg alloys and of Fe, Si, Cu, Ti, in Al-4-4.5%Mg-0.5%Mn-0.2%Cr alloy on the corrosion resistivity, changes of tensile properties during immersion of the samples in the sea-water for up to 12 months were tested.
It is seen that, in general, Al-Mg binary alloys are the best and the addition of Mn, Cr, Fe or Cu decreases corrosion resistivity, wheras the effects of Si, Zn and Ti being small.

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The change of tensile properties of the sample (0.5mm thick) under soft or stabilized state during immersion with or without stress in salt-water for up to 12 months, was investigated for the purpose of clarifying the cffect of Mn, Cr, Fe, Si, Cu, Zn and Ti as wellas that of rolling condition on the corrosion resistivity of Al-3-5% Mg alloys.
The results obtained are as follows:
1. Mn, Cr, Fe or Cu decreases the sesistivity.
2. The effect of Mg, Si, Cu, Zn or Ti, on hot working temperatureor the preheating condition of ingot is not so remarkable.

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Mechanical properties and macro or X ray structurs of Al-3-5%Mg 0-0.75%Mn 0-0.5%Cr alloys extruded by 1, 000 ton press to 4×40×40mm angle section were examined, relating to the extruding temperature and preheating of ingot. Results obtained are as follows:
1. Mn and Cr bring about the fibrous structure in the section.
2. Tensile properties of the sections are influenced to some degree by the amount of fibrous structure and grain size.
3. Mg, Mn and Cr increase strength, wheras Mn and Cr decrease elongation.
4. In some cases, the properties of the alloys are considerably influenced by the extruding temperature and preheating of ingot.

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A cladding behaviour between materials having different flow resistance was investigated by hot-rolling, hot-extrusion and cold-rolling. The results obtained were summarized as follows:
(1) With regard to the cladding by hot-rolling, good bonding behaviour could be obtained if a pair of metals was sufficiently reduced together by a rolling pass, even though the metals had considerablly different flow resistances between them.
(2) In the case of cladding by hot extrusion the inverted-extrusion method was recommended in view of the flow of metals.
In the case of cladding by cold-rolling, some defects such as “crack” and “ripple” occurred.
(3) Whcn the ratio of thickness of cored to outside metal was constant, the pitch of “ripple” on the bonded interface became wider with the increase of total thickness.
(4) When the total thickness was constant, the larger the ratio of individual thickness, the better the bonding behaviour. In the case of the larger ratio of individual thickness, the cracking in the harder material was scarcely observable up to higher rolling reduction.
(5) When the total thickness and the ratio of individual thickness were constant, the defference in hardness of out-side material-64 V. P. N-160 V. P. N-had no influence on the occurrence of “crack” and “ripple” on Ti-24s pair. And the increase of rolling reduction resulted in the deeper “ripple”, the pitch of which, however. being unaffected.
(6) The rolling reduction to make necessary bonding became lower with the total thickness increased.
(7) Occurrence of “ripple” was caused by over-stretching of softer metal, and the ripples resulted in the “cracking” of harder metal.

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The author verifys that the titanium and its alloys prepared by the method which is reported in the 1st part of this report, have high purity and no segregation, and that the ingots of them are free from internal defect, discussing physical properties, heat treatment properties, micro-structure and mechanical properties of them. This technical report does not contain the part which deals with the melting procedures and properties of ferrous metals.

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The determinaton of carbon in titanium and titanium alloys has been investigated using modified combustion weight method of carbon determination of iron and steel.
The results are as follows:
(1) The titanium can be burned in oxygen, using copper flux at 1, 200°C or tin flux at 1, 400°C. But the sampe of high carbon content (above 0.05%) can be burned in oxygen without flux at 1, 400°C.
(2) In order to shorten the time reguired for one sample analysis and simplify the combustion of sample, high frequency combustion method instead of usual electrical resistant-heating furnace method was used. By the high frequency combustion method, sample of low carbon content (under 0.03%) is burned in oxygen without flux and the sample of high carbon content (above 0.03%) can be burned in oxygen using pure iron flux. Analytical time is shorter by 10 minutes than that of electrical resistant-heating furnace method.
(3) Analytical results of those two methods for various samples of materials agree very well. The degree of precision of the sample of low carbon content (under 0.05%) is ±0.001% for electrical resistant heating furnace method and ±0.002% for high frequency combustion method.

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As hydrogen in titanium and alloys is considered an undesirble impurity, determination is, a matter of importance. In this paper a method and apparatus for the determination of hydrogen in titanium and titanium alloys by vacuum fusion, vacuum extraction and combustion method are reported. The vacuum fusion method is one of the standard ones but its apparatus is compilated and requires skilled operation. The vacuum extration method is simple, rapitd and allowably complet.
By the combustion method, the sample is burned in oxygenin a high frequency combustion fuenace and the gas is passed through hot copper oxide to ensure complete oxidation of hydrogen to water which is absorbed in a phosphorous pentoxide absorption tube.
Applying the vacuum extraction method, the content of hydrogen of commercially pure titanium and titanium alloys was measured.
The results obtained are as follows:
(1) The evolution of hydrogen from titanium is easy and the variation of diameter of the specimen is affected when it is of bar shape.
(2) It is found that the hydrogen content of titanium ingot has something to do with the hardness (probably exygen content).
(3) A little higher hydrogen content is obtained in the centre and bottom part of titaniumm ingot.
(4) Also, a little higher hydrogen content is obtained in the titanium sheet and bar than the titanium ingot.
(5) Hydrogen content of the titanium sheet and bar can be regurated by the method of treatment.
(6) When titanium is dipped in the nonoxidizing acid such as HCl or H₂SO₄, the hydrogeon content in the specimen is increased remarkably.
(7) So high hydrogen content of titanium and titanium alloy as to affect the charpy impact value is not obtained.

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