巻号一覧
20 巻, 3 号
選択された号の論文の6件中1～6を表示しています
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平松 剛毅, 宮木 美光, 辻 美紘1970 年 20 巻 3 号 p. 103-109
発行日: 1970/03/31
公開日: 2008/07/23
ジャーナル フリーExperiments were conducted to investigate the effects of cold working on mechanical properties and stress corrosion resistance of structural Al-Zn-Mg alloys, and the relation between the stress corrosion cracking and shear cracks was discussed.
The results obtrained were summarized as follows.
(1) Tensile strength, yield strength, and hardness of the high temperature aged material were higher than those of the low temperature aged one. The above values were increased with the increase of cold reduction ratio in the both materials. However, the rates of increase in these values by cold reduction were more remakable in the low temperature aged material than in the high temperature aged one. Then, at the cold reduction ratio of 20%, these values of the low temperature aged material were higher than those of the high temperature aged one.
(2) Stress corrosion resistance in the short transverse direction was higher in the low temperature aged material than in the high temperature aged one. The resistance was decreased with the increase of cold reduction ratio in the both materials. However, the rate of decrease in the resistance by cold reduction was more remarkable in the low temperature aged material than in the high temperature aged one. Then, at the cold reduction ratio of 20%, the reistance of the low temperature aged material under higher applied stresses was lower than that of the high temperature aged one.
(3) The life of shear cracks was longer in the high temperature aged material than in the low temperature aged one.
(4) Shear cracks are supposed to be stress corrosion cracking due to the residual stress caused by shearing. The reasons for higher stress corrosion resistance of the low temperature aged material and higher shear crack resistance of the high temperature aged one would be as follows.
(a) The reduction ratio of cold working in the sheared part is about 20%.
(b) Assuming that the residual stress caused by shearing is equivalent to the yield strength of the sheared part, the stress of the low temperature aged material is higher than that of the high temperature aged one.
(c) In the low temperature aged material, stress corrosion resistance is higher but at cold reduction ratio of 20%, the resistance under higher applied stresses is lower. Accordingly, shear cracks are more likely to occur in the low temperature aged material than in the high temperature aged one.抄録全体を表示PDF形式でダウンロード (1040K) -
開放型における盛り上がり変形について(第1報)前島 敬一, 師岡 利政1970 年 20 巻 3 号 p. 110-117
発行日: 1970/03/31
公開日: 2008/07/23
ジャーナル フリーAluminum and its alloys have widely been utilized as the forged products in the various industries. However, few studies have been reported on the fundamental investigations such as deformation process and on the effects on metallurgical and mechanical properties.
In this paper, the experimental results are presented on the deformation process of open-die extrusion.
Two sorts of measuring methods were used for the study of deformation process in this work. One of them was the measuring of the change in contact pressure between the specimen and the inside surface of die during the forging with sensitive pin (the sensitive pin method); and the other was the measuring of the difference in size and shape of the specimen between before and after the compression (the external form method).
The both methods were alsways attempted for the specimen of the same shape and the authors investigated the deformation processes under various conditions by means of the results of the both methods.
The results of experiments were summarized as follows:
1) The change in contact pressure during the forging was continuously measured by the sensitive pin method.
2) Open-die extrusion process in the forging consisted of three stages. The change in contact pressure was observed during the deformation at each stage.
3) The both results of the two methods were in quantitatively good agreement with each other.抄録全体を表示PDF形式でダウンロード (847K) -
財満 鎮雄, 広野 雅道, 桜井 柳治1970 年 20 巻 3 号 p. 118-128
発行日: 1970/03/31
公開日: 2008/07/23
ジャーナル フリーSince a great change is introduced by heat treatments in structures or mechanical properties of aluminum casting alloys, there would also be produced some change in machinability of the alloys. However, few studies concerning this field have been reported and many problems remain still unsolved.
This paper describes the turning tests made on so-called copper silumin, aluminum casting alloy 4B (JIS AC4B), for the object of examining the effects of five sorts of heat treatments; or T2-, T4-, T5-, T6- and T7- treatments. Cutting resistance, cutting temperature, roughness of finish surface, growth of deposit on tool surface, chip formation, etc. were discussed to find out a relation between machinability in turning and heat treatments.
The results were summarized as follows.
The cutting resistances of the heat treated materials were generally higher than that of F-material (as cast) and in particular, that of T7- material was the highest. The ascending order of the resistance was generally arranged as follows:
T2-<T5-<T6-
The cutting temperatures of T4- and T6- materials, which showed comparatively higher hardnesses, were higher than those of the soft materials; T2-, T5- and T7- materials. The roughness of finish surfaces of T4- and T6- materials was good, but that of T2- and T5- materials was bad.
The growth and adhesion of tool deposit, or built-up edge, etc., was very frequently observed on T2- and T5- materials, but seldom on T4- and T6- materials.
Chips were produced in continuous linear form at low cutting speed, but at higher speed, the chip figures were gradually changed to chopped or ground form, and they were scattered in all directions. These phenomena were particularly observed in turning of T4- and T6- materials.抄録全体を表示PDF形式でダウンロード (3432K) -
須藤 延, 阿部 隆, 相沢 浩司, 長谷川 実1970 年 20 巻 3 号 p. 129-136
発行日: 1970/03/31
公開日: 2008/07/23
ジャーナル フリーCorrosion resistance of Al-Zn alloys was studied by potentiodynamic method.
Specimens used were Al-0%Zn, Al-0.1%Zn, Al-0.3%Zn, Al-0.7%Zn, Al-1%Zn and Al-5%Zn alloys. Experiments were conducted in 0.1N HCl, 0.1N NaOH, 5wt% NaCl aqueous solution and city water.
The results obtained by potentiodynamic method and immersion tests were summarized as follows:
(1) When immersed in the acid, there was correlation between the weight loss by corrosion and current intensity for corrosion obtained from the cathodic polarization curves of Al-Zn alloys by overvoltage-intercept method. The corrosion resistance of the alloys containing Zn of more than 0.7% was lower.
(2) When immersed in the alkali, the electrochemical behavior of the alloys exhibited a typical transition between active and passive states. The critical current for passivation and the current for keeping passivity as well as the weight loss by dissolution were decreased with the increase in Zn content of the alloys.
(3) When immersed in naturally aerated 5% solution of NaCl, the current for limiting diffusion calculated from the cathodic polarization curves of the alloys as well as the weight loss by corrosion was increased with the increase in Zn content of the alloys.
(4) When immersed in city water, the polarization curves of the alloys were nearly identical with those in 5wt% solution of NaCl. The diffusion current in cathodic regions as well as the weight loss by corrosion was increased with the increase in Zn content of the alloys.抄録全体を表示PDF形式でダウンロード (927K) -
長浜 勝介, 三木 功1970 年 20 巻 3 号 p. 137-144
発行日: 1970/03/31
公開日: 2008/07/23
ジャーナル フリーIt is well known that a small amount of iron, usually contained in commercial aluminum and its alloy as an impurity, has great effects on grain size and aggregate structure after recrystallization. However, its mechanism remains still unsolved.
The activation energy of self-diffusion of the iron atom in aluminum was estimated to be 38.1±0.5 kcal/mol by one of the authors1) (Miki). The value was comparatively higher than that of aluminum or copper in aluminum. The sluggishness of the behavior of the iron atom such as diffusion and precipitation in aluminum and the stability of iron compounds were explained by the above fact.
According to Hirano et al2)., iron atom is likely to diffused through dislocations by pipe diffusion under certain conditions. Then, the precipitation of iron compound is expected to be accelerated by the increase of dislocation density in aluminum matrix by means of deformation.
The object of this study was to examine the precipitation of iron compound from deformed super-saturated aluminum matrix during recovery and recrystallization by means of hardness and electric resistivity measurements and by direct observation of thin films by an electron mircoscope. The alloys used were Al-0.043wt%Fe and Al-0.043wt%Fe-0.056wt%Si.
The results obtained are summarized as follows:
1) Precipitation of iron compound was accelerated by cold working and its rate was proportional to the degree of cold working. The acceleration was especially evident at the early stage of recrystallization process, and it occurred in the both processes of nucleation and crystal growth.
2) Retardation of the recrystallization process was observed. It would be attributed to the pinning of subboundaries by the precipitates, which were formed within the boundaries at the early stage of recrystallization.
3) The precipitates of iron compound, which had been formed during the recrystallization, was observed by an electron microscope, and were identified as Al3Fe by diffraction patterns. The precipitates in this case were in globular form, quite different from those observed in undeformed specimens. They were not homogeneously distributed and their sizes were classified into two groups. The larger ones (0.5several microns) were supposed to be nucleated within subboundaries or grain boundaries. The smaller ones (less than 0.1μ) were supposed to be nucleated on dislocation lines.抄録全体を表示PDF形式でダウンロード (1895K) -
河野 修1970 年 20 巻 3 号 p. 145-155
発行日: 1970/03/31
公開日: 2008/07/23
ジャーナル フリーPDF形式でダウンロード (2145K)
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