Electric and mechanical properties of wet galvanized aluminum wires of two different grades (99.999 and 99.85%) were investigated after diffusion annealing.
Considerable differences were observed in electric conductivity and mechanical properties (such as 0.2% proof stress, maximum tensile strength, and ductilities in twisting and repeated bending test) between the wire of high purity grade with coarse grains and of commercial purity grade with fine grains. As the results of photomicrography and X-ray microanalysis, the reason for these differences were due to the behavior of boundary diffusion.

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These investigations were undertaken concerning the effects of shapes of round and rectangular specimens on the tensile properties of aluminum alloys.
The specimens were machined from 30mm thick plate of an aluminum alloy designated as 5052-O.
The principal results obtained were as follows:
(1) The size and shape of test specimens had practically no effects on the proof stress and tensile strength of the material.
(2) The curve representing the relation between δ and L₀/√A (in whichδ: elongation percentage, L₀: gaug elength, and A: cross-sectional area of the specimen) of round specimens was virtually identical with that obtained from rectangular specimens having nearly the same width as thickness. However, it was found that δ for the same value of L₀/√A was slightly decreased with the increase in the ratio of width to thickness in rectangular specimens.
(3) When L₀/√A≥10, the values of δ were little different between round and rectangular specimens independent of their sizes and shapes.
(4) In round specimens, the region of shoulder constraining the strain distribution near the end of the reduced section (l_f) was nealy equal to the length of the diameter from the end of the straight section.
In rectangular specimens, the value of l_f/W (W: width of the specimen) was increased with the decrease in the ratio of width to thickness, and it was approximately equal to 1 in square cross-sectional specimens.
(5) The reduction of area in the fracture section was slightly descreased with the increase in the ratio of width to thickness in specimens of rectangular section, but it was nearly constant in round specimens of different diameters. There was very little difference of the value between round and square cross-sectional specimens.

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In this paper, there is discussed the turning machinability of aluminum-silicon alloy castings. The alloys examined were the materials for members of automobile engines. They were composed of the chemical compositions in Table 1 and were designated as A, B, and C according to silicon contents of 22, 24, and 13%, respectively.
The types of cutting tools used in the experiments were 31-2 and 33-2 of sintered hard alloy K-10. The conditions of machining were as follows: orthogonal cutting for materials A and B, and oblique cutting for material C; and the details of other conditions will be given in this paper.
The results obtained were as follows:
(1) Cutting resistance
The cutting resistance was very lower than that in iron and steel, and it depended upon silicon content and the formation of built-up edge.
(2) Roughness of finished surface
The surface was smoother in the materials A and B under low cutting resistance. The quality of surface depended upon plowing up of primary silicon crystals and chattering of the tool. Whereas, the surface roughness of the material C was approximate to the theoretical value.
(3) Chip treatment
In the materials A and B, chips were curled into a small radius and ruptured into small fractions, which were seattered around the tool holder. Whereas, the maximum length of the chips in the material C was about 200mm, which were easily treated in the experiments.
(4) Built-up edge
Formation of built-up edge was observed in the range of low cutting speed in the materials A and B. Whereas, it was observed even at the cutting speed of 240m/sec. in the material C. The critical cutting speed for its formation largely depended upon silicon content.
The built-up edge densely covered the edge from the backrake surface to the flank and severely lowered the quality of finished surface.

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This paper describes local stress relief heat treatment for butt-joints of a 5083-O plate. The following results were obtained by experiments.
(1) In order to relieve the residual stress at a butt-joint, the region of the maximum stress had to be heated at least above 150°C. For relaxing it to about half a degree of as-welded state, the heating had to be above 250°C and for virtually relieving it, the heating above 350°C was needed.
(2) Among three heating methods in these experiment, the best results were obtained by the heating method of reciprocation. The results of one or two-point heating method were inferior to those of the above method.
(3) The degree of stress relief annealing tended to be similar to the reduction in high temperature tensile strength of the base metal rather than its yield strength.

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The effects of change in specimen dimension on elongation percentage of an aluminum alloy was investigated for round specimens having various lengths in reduced section and radius of fillet. The specimens were machined from 5052-O alloy plate of 30mm thick. The size of specimens suitable for obtaining tensile characteristics of the material was determined.
The principal results obtained were as follows.
(1) The length of the region of shoulder constraining strain distribution near the end of the reduced section was nearly equal to the length of the diameter of reduced section (when measured from the end of the straight section) independent of fillet radius.
(2) It was desirable that the length of the reduced section of round specimens, L_c, would be determined by the following formula: L_c≥L₀+2D (in which L₀: gauge length, D: diameter of the specimen) for eliminating the effect of shoulder fillet radius on the elongation percentage obtained by tension tests.
(3) The length of the neck, which had previously been measured along the specimen before the test, was 23D for the materialused.
(4) It was desirable that the full length of neck remained within the gauge length when rupture occurred around the center of the specimen. Accordingly, the length of the reduced section of round specimens would preferably be in the range of L_c≥5.5D.

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