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Volume 19, Issue 1
Displaying 1-6 of 6 articles from this issue
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Shiro SATO1969 Volume 19 Issue 1 Pages 1-7
Published: January 30, 1969
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSTension tests were conducted on round bar specimens, having the long parallel lengths of about 220 mm produced by cutting out of thick plates of Al-Zn-Mg T 4 and T 6 alloys in thickness of 15, 20, 30, and 35 mm.
The main results obtained were as follows.
(1) The relation between tensile strength (σB) and proof stress (σ0.2) is expressed as follows.
σ0.2/σB = 0.66 for T 4 alloys
σ0.2/σB = 0.91 for T 6 alloys
(2) No effects of age-hardening were found in T 6 alloys, but it was evident in T 4 alloys that tensile strength and proof stress were considerably improved by the effects of age-hardening.
(3) The apparent fractures after shearing were different between T 4 and T 6 test pieces. The former exhibited little local contraction, which the latter exhibited a relatively large necking down.
(4) The curve expressing the relation between δ and L0/√A in T 4 alloys (in which δ: elongation percentage, L0: gauge length, and A: cross-sectional area of the apecimen) was more likely to be horizontal for smaller value of L0/√A than that value in T 6 alloys. Then, elongation percentages would be practically expressed with considerable accuracy for the values of L0/√A ≥ 5 in T 4 and L0/√A ≥ 10 in T 6 alloys.
(5) The specimens had anisotropy in structure, because they had been cut out of rolled plates. Accordingly, they had elliptical cross-section. The value of mechanical anisotropy was defined and expressed as k.
(6) Supplementary tests were conducted in order to compare elongation percentage of a plate specimen with that of a round bar specimen of the same material. If the value of L0/√A was constant, the values of elongation percentage were almost the same in the both specimens.View full abstractDownload PDF (921K) -
Shigeo ZAIMA, Masaji IIO, Kenichi SHIRAKAWA1969 Volume 19 Issue 1 Pages 8-16
Published: January 30, 1969
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSSeveral sorts of cutting fluids having various viscosities were used in drilling of aluminum alloys and their effects on drilling resistance, drilling temperature, drilling accuracy, state of drilled surface, disposal of chips, etc. were discussed. Since the reproducibility in supplying the fluid was not reliable, the drilling tests were conducted by dipping the whole specimen in the fluid. The results were summarized as follows.
Nose angle of 118° and lip clearance of 12° were effective in drilling of aluminum alloys with cutting fluids when the effects on drilling temperature and roughness of drilled surface were taken into consideration. Among some kinds of drilling resistance, the viscosity of the liquid had little effects on torque; but the effects on thrust and drilling time were more powerful than those in dry drilling. (These values were higher than those in dry drilling). However, high viscous fluids were more effective, because they gave the lower values than those in dry drilling. When cutting speed was low, the drilling temperature was lower than that in dry drilling. The roughness of drilled surface was finished better than that in dry drilling, and also better effects were given on the disposal of chips, appearance of burrs at the outlet of hole, etc. However, no remarkable effects were found on the enlargement of hole diameter.View full abstractDownload PDF (989K) -
Studies on the extrusion of Al-Mg-Si alloys(1st Report)Tsuneo TAKAHASHI, Yoshikazu KOBAYASHI1969 Volume 19 Issue 1 Pages 17-23
Published: January 30, 1969
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAl-0.6% Mg-0.4% Si alloy was extruded under various soaking conditions, reduction ratios, and extrusion temperatures. The effects of soaking conditions on extrusion pressure and mechanical properties and texture of extruded rod were examined.
The following results were obtained.
(1) Under the soaking condition of at 490560°C for 816 hrs, the extrusion pressure was slightly lower with the rise of temperature and the increase of soaking time.
(2) The mechanical properties of extruded rod were more improved with the rise of extrusion temperature in the range of 400520°C.
(3) The proper annealing condition (T5 treatment) of the extruded rod was at 175°C for 3 hrs.
(4) The extruded rod of this alloy had double texture of <111> and <100>. The ratio of <100> structure to the other was larger with the rise of extrusion temperature and also larger in the middle of the rod than its front tip.
(5) The tensile strength of the extruded rod decreased with the increase in the ratio of <100> structure to the other.View full abstractDownload PDF (1199K) -
Shigenori HORI, Mitsushige KITAZAWA1969 Volume 19 Issue 1 Pages 24-27
Published: January 30, 1969
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe fatigue behavior of commercially pure aluminum plates of various grain sizes was studied by using a repeating type bending machine and the following conclusions were drawn.
Fatigue limit in alternate bending stress was increased with the decrease of grain size and its dependence upon the grain size was nearly identical with that of tensile strength upon the grain size.
Hardening, resulting from the alternate stress, exhibited a linear relationship to the logarithmic value of repeating times. In the early stage of testing (less than 7% of fatigue limit), the degree of hardening was low, but it was led to relatively higher values with subsequent cycles of bending. The conversion point of hardening by the repeated cycles did not depend upon grain size of the specimen.
By intermediate annealing of the specimen after subjected to the repeated cycles of less than 7% of the the expected life, the number of total cycles to the perfect failure was increased. However, damage of the specimen was irrecoverable after it was subjected to the cycles of 10% of the expected life.View full abstractDownload PDF (492K) -
Shozo YOSHIOKA, Yutaka NAKAYAMA, Norio HOSOKAWA, Kenya NAKAI1969 Volume 19 Issue 1 Pages 28-33
Published: January 30, 1969
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe figures and crystal structures of intermediate α' phases in Al-Zn alloys artificially aged at high temperatures were studied by means of transmission electron microscopy and X-ray diffractometer as functions of aging time.
At the earlest stage of aging, a lenticular α' phase parallel to {111} matrix planes was present and finally it grew up to about 3, 000 Å in dia. and up to about 200 Å in thickness. Interference fringes were detected by electron microphotographs in these precipitates. Most of these fringes having spacings of the order of several hundred Angstroms originated from the Moiré fringe contrast, but a part of them would originate from the displacement fringe contrast.
It was determined by the Moiré fringe contrast that the astructure of the lenticular α' phase was rhombohedral lattice with a = 3.991 Å and α = 91°45'. The lenticular α' phase was converted into parallelopiped figure, which was achieved by the introduction of misfit dislocation to the interface. In final, the α' phase was changed from parallelopiped to prismatic figure.View full abstractDownload PDF (2082K) -
Kentaro TANIUTI, Toshihiko SATO1969 Volume 19 Issue 1 Pages 34-40
Published: January 30, 1969
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (793K)
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