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Volume 21, Issue 1
Displaying 1-8 of 8 articles from this issue
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Ichiro NAKAYAMA1971 Volume 21 Issue 1 Pages 1-6
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
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Growth and reversion of G. P. zones in aluminum alloys. (3rd report)Yoichi HIROSE, Kazuhiko ASANO, Kenichi HIRANO1971 Volume 21 Issue 1 Pages 7-11
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSReversion characteristics of Al-5%Ag alloy and the effects of a small amount of Sn were examined by measurements of electric resistivity and tensile strength. It was observed that the resistivity was increased to the maximum, and then, decreased during reversion heat-treatments at 120200°C after ageing at 70°C in the same manner as seen in Al-20%Ag alloy. Sn had no effects on the rate of reversion, especially when the alloy had been aged for a long period at 70°C.
However, different from Al-20%Ag alloy, the resistivity and the strength of Al-5%Ag alloy did not show abrupt changes near 170°C which corresponds to ε-η transition temperature of G. P. zones according to Baur and Gerold. Then, it was concluded that ε-η transition temperature in Al-5%Ag alloy was higher than that given by the metastable miscibility gap determined by Baur and Gerold and the reversion was caused by the re-dissolution of G. P. zones. It was contrary to the behavior of Al-20%Ag alloy, in which the reversion is caused by the transition from η into ε.
Diffusion processes during the reversion was discussed in reference to the metastable miscibility gap.View full abstractDownload PDF (1108K) -
Studies on sealing of anodic oxide films of aluminum. (1st report)Hiroshi KAWASE1971 Volume 21 Issue 1 Pages 12-18
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSEffects of sealing conditions (sealing time and pH value of sealing solution) on sealing results were studied by measureing the impedance and L value in dyeing test of anodic oxide films.
Aluminum specimens anodized in sulfuric acid were sealed in boiling distilled water. The pH of the sealing solution was adjusted with dilute H2SO4 or NaOH.
The results obtained were as follows:
(1) The impedance of anodic oxide films was increased with the increase in sealing time.
(2) The effect of alkaline solution (pH = 710) on sealing was more powerful than that of acid solution (PH = 24).View full abstractDownload PDF (971K) -
Tsuneo TAKAHASHI, Tsuneo SAGA, Tomohiko MITSUMORI1971 Volume 21 Issue 1 Pages 19-26
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSTurning test were conducted on JIS AC8A aluminum alloy casting to study the effects of Na and P on its machinability.
The results obtained were summarized as follows:
(1) The cutting resistance of the specimen treated by Na was slightly higher than that of the specimen treated by P.
(2) The roughness of the finished surface was nearly under the same conditions between the both specimens treated by Na and P. Remarkably irregular surface was found in the range of low cutting speed owing to the adhesion of built-up edge on the tool rake face and the rising of machined surface during cutting. However, the built-up edge disappeared with the increase of cutting speed and the roughness of machined surface approximated to the theoretical roughness.
(3) The chip forms and chip treatments were nearly under the same conditions between the both specimens treated by Na and P.
(4) The tool life for the specimen treated by P was much shorter than that for the specimen treated by Na with the increase of cutting speed.View full abstractDownload PDF (2032K) -
Takeshi INOUE, Masao KATO, Kenjiro GOTO, Goro ITO, Yoshihiko SHIMIZU1971 Volume 21 Issue 1 Pages 27-35
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe pitting corrosion of commercially pure aluminum was investigated in various solutions prepared by adding 5ppm of chloride ion, 5ppm of an inhibitor (a kind of ions of sulfate, silicate, and phosphate), and 0.55ppm of an oxidizing agent (a kind of hydrogen peroxide, chlorine water, calcium hypochlorite (bleaching powder), sodium chlorite, and nitric acid) to deionized water. The pH of the solutions was adjusted to 3.010.5 with dilute hydrochloric acid or sodium hydroxide solution. Corrosion tests were conducted in stagnant water at 35°C for 100hrs. The potentiostatic polarization measurements were also performed on some typical solutions.
The results obtained were summarized as follows:
(1) In the solution of pH range of 5.08.5 which contained no oxidizing agents other than the dissolved oxygen, the pitting corrosion of aluminum was very little when chloride and sulfate ions or chloride and silicate ions were contained. Whereas, a few macropits were observed in a solution containing chloride and phosphate ions.
(2) The addition of 0.55 ppm of an oxidizing agent such as hydrogen peroxide or free chlorine to these solutions had powerful effects on the formation of pits. In particular, in a solution containing chloride and phosphate ions together with one of the above oxidizing agents, a large number of macropits were formed in a comparatively short time.
(3) In general, the effects of these oxidizing agents on the formation of pits were less on the alkaline side rather than the acidic side.
(4) The addition of 0.510ppm of nitric acid to the solution containing chloride and sulfate ions or chloride and phosphate ions accelerated pitting corrosion.
(5) The effects of dissolved ions and oxidizing agents on pitting corrosion of aluminum mentioned above were discussed with respect to the polarization characteristics of aluminum in these solutions.View full abstractDownload PDF (1225K) -
Studies on solidified structure and properties of Al-Si-Cu alloy die castings. (1st report)Muneo SUZUKI, Kazuyuki FURUMOTO1971 Volume 21 Issue 1 Pages 36-45
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSStudies were made on the influence of "mass effect" on physical and mechanical properties of Al-12Si-Cu alloy (JIS ADC12) die castings affected by the change in wall thickness from 2 to 10mm.
The following results were obtained.
(1) Specific gravity, coefficient of thermal expansion, modulus of elasticity, hardness, ultimate tensile strength, 0.2% yield strength, elongation, bending strength flexibility, compressive strength, compressive yield strength, compressive strain, shearing strength, impact strength and fatigue strength depended upon the wall thickness. As the results of analysis of variance, their values were significant on the significant level of 99 or 95%.
(2) According to the regression analysis, the relation between the wall thickness (t) and the strength (σ) was expressed by the following general equation.
σ=a•t-n
Where a and n mean constants depending upon material properties and strength.
The equation showed that the "mass effect" was more remarkable with the increase in the value of n.
The values of the strengths would be expressed by the following equations:
Ultimate tensile strength σt=31.8t-0.13
0.2% yield strength σ0.2=20.5t-0.15
Bending strength σb=69.4t-0.13
Compressive strength σc=47.6t-0.014
Shearing strength σs=22.1t-0.02
Fatigue strength σf=15.3t-0.11
However, the value of impact strength did not conform to the general equation, but was expressed by a curve having a minimum at 4mm of the wall thickness.
(3) The ration between other strength and the ultimate tensile strength were calculated to be as follows:
σb=2.2σt σc _??_ 1.8σt σe _??_ 0.8σt σ5 _??_ 0.5σt
The above results approximately corresponded with those previously reported on non-ferrous and other metals.View full abstractDownload PDF (1689K) -
Wolfgang Gruhl, [in Japanese]1971 Volume 21 Issue 1 Pages 46-54
Published: January 30, 1971
Released on J-STAGE: July 23, 2008
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1971 Volume 21 Issue 1 Pages e1
Published: 1971
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (34K)
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