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Volume 37, Issue 6
Displaying 1-17 of 17 articles from this issue
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Ryoichi Nozato, Harusige Tsubakino1973 Volume 37 Issue 6 Pages 571-578
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe precipitation of cadmium from lead-rich solid solution was investigated for a lead-1.5 wt% cadmium alloy aged isothermally in the temperature range of −25 to 150°C, by correlating the results of metallographic observation and micro-hardness measurement to electrical resistivity measurements. The changes in the metallographic structure, micro-hardness and resistivity with ageing time were found to depend on three discontinuous precipitations and one continuous precipitation. Below 65°C, discontinuous precipitation and continuous precipitation start simultaneously, with an activation energy of 6 kcal/mol. Above 65°C, the precipitation of cadmium start first by discontinuous precipitation, with an activation energy of 15 kcal/mol. With progressing isothermal ageing time, continuous precipitation takes place. The rate-controlling process in the each discontinuous precipitation above and below 65°C is considered to be volume and boundary diffusions of cadmium in lead, respectively. The growth rates of the both discontinuous precipitations are greatly reduced by the concurrent continuous precipitation. A divergence of lamellar spacing in the cell of the discontinuous precipitation was observed, irrespective of ageing temperature. This phenomena may be attributed to the influence of the stable precipitate, which had been formed by the continuous precipitation in the grain center region, upon the discontinuous precipitation.View full abstractDownload PDF (994K) -
Shojiro Ochiai, Makoto Mizuhara, Yotaro Murakami1973 Volume 37 Issue 6 Pages 579-588
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe cold rolling characteristics of ductile fibre-reinforced Mo/Cu, Mo/Cu-Cr and W/Cu composites prepared by vaccum infiltration technique have been investigated. These composites were cold rolled parallel or perpendicular to fibres in steps of 10% reduction in thickness to maximum 90%. Deformation behaviour of composites as well as matrix and fibre separately were studied. Tensile tests were carried out. Tensile strength values of the Mo/Cu composites agreed well with those calculated from the rule of mixture in which work hardening of fibre and matrix was considered. In the Mo/Cu-Cr composites, the tensile strength showed lower values than those calculated from the rule of mixture, probably, according to damages by cold rolling of Mo-Cr solid solution layers formed at interfaces of Mo fibres during preparation. In the W/Cu composites, the tensile strength had maximum values at 30∼40% reduction in thickness because of a lower ductility of W fibres.View full abstractDownload PDF (1273K) -
Takashi Kuse, Hideo Hirayama, Teruji Makuuchi, Yasunobu Hirasawa1973 Volume 37 Issue 6 Pages 588-593
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFe-18 Cr sealing alloys containing Al and Ti have been prepared by vacuum melting, and oxidized in air and wet hydrogen. The electrical resistivities of the oxide films on the alloys have been measured. Mutual relations between the electrical resistivity and structure, morphology of the oxide film, interface between the metal and the oxide film have been investigated. The results obtained are as follows.
(1) Electrical resistivities of the oxide films on the alloys oxidized in air are not affected by the additions of Al and/or Ti, and are in the range of 103∼104 Ω-cm. In the case of oxidations in wet hydrogen, electrical resistivites of the oxide films on the alloy which was not added and alloy containing Al and Ti are in the range of 103∼104 Ω-cm, but the alloys containing Al or Ti alone show the electrical resistivities of 107∼1010 Ω-cm and 105∼109 Ω-cm respectively.
(2) By the heat treatment in air after the oxidation in wet hydrogen, the electrical resistivity of the oxide films on the alloys containing Al or Ti alone or none of them increases with the temperature of heat treatment. But the resistivity for alloys containing Al and Ti increases with the temperature of heat treatment and shows a maximum at 1000°C, and beyond this critical temperature, it becomes to smaller than the initial value.
(3) Electrical resistivity of oxide films is supposed to change by the structure, charge carrier density and the increase or decrease of metal and oxygen ions.View full abstractDownload PDF (639K) -
Hideaki Kawabe, Akira Ohtsuka, Masaharu Takamura, Tomoharu Yamada1973 Volume 37 Issue 6 Pages 594-598
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe formation mechanism of the work-deformed surface layer was studied for high purity (001) single crystals of aluminum. Scratch deformation was given by diamond styluses in [100] and [110] directions. The surface characteristics were examined by X-ray and the subsurface structure was directly observed by electron microscopes. The results are as follows:
(1) The direct transmission observations of the scratch-deformed surface layer show that the well-developed cell structures are existing under the groove, and beyond the groove the dislocation structures similar to those obtained by tensile deformation are recognized. The structure peculiar to the scratch deformation can only be observed near the groove; at the center of groove cell structures having a very small size are somewhat elongated in the direction of scratch, and at the ridge of the groove long bundles of dislocations are running parallel to the scratch direction.
(2) The geometrical characteristics of these deformed structure are not much affccted by the direction of scratching nor by the cone angle of diamond stylus. The misorientation of neighboring cells at the center of the groove, however, changes with the latter. Thus the cone angle affects the deformed structure; the smaller the cone angle the greater the amount of deformation at the center of the groove.
(3) The scratch-deformed structure is formed by the superposition of (i) the dislocation structure induced for the ridge formation by the indentation of the diamond cone on (ii) the dislocation structure induced by the rotation of the crystal accompanying the passage of diamond stylus.View full abstractDownload PDF (725K) -
Hiroshi Oikawa, Masahiro Maeda, Seiichi Karashima1973 Volume 37 Issue 6 Pages 599-603
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTensile creep behavior of Fe-3.5 at% Mo solid solution (class I alloy) was studied in argon atmosphere at 850°C in the stress range 1.1 to 4.0 kg/mm2. Creep structures were examined and some activation parameters were determined in the steady-state stage. Microstructures of the alloy were similar to those of alpha-iron. Internal stress obtained by stress-transient dip test technique was low and independent of creep stress; σi=0.35±0.03 kg/mm2. Effective-stress dependence of steady-state creep rates, \dotεs, can be represented by \dotεs∝σ*n*, in which n*=2.7±0.1. Effective-stress dependence of the dislocation density within subgrains, ρ, can be represented by ρ∝σ*nρ*, in which nρ*=1.5±0.2. When a relation, \dotεs∝ρv, is assumed, the velocity of moving dislocations, v, is proportional to the effective stress, σ*; the dislocation motion is viscous one. Stress relaxation curves also indicate that v is proportional to σ*. It may be concluded that creep deformation of Fe-3.5 at% Mo alloy is controlled by one of the microcreep processes, perhaps by solute-atmosphere dragging, under the present condition.View full abstractDownload PDF (687K) -
Kunio Shiobara1973 Volume 37 Issue 6 Pages 604-611
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of OH−, SO42−, and NO3− ions were examined on the pitting and crevice corrosion of 18 Cr-8 Ni stainless steel. Furthermore, some additional experiments were performed on the pitting and crevice corrosion. The results are summarized as follows: (1) The critical potentials for the pitting and crevice corrosion obtained by galvanostatic polarization at a current density of 2 μA/cm2 were in good agreement with the results obtained in a previous report. (2) The repolarization measurements indicated that the processess of pitting and crevice corrosion were the dissolution by the oxidizing action in the initial stage and turned out to be an active dissolution as the corrosion proceeded. (3) In the all solutions examined, the corrosion of the specimen in the crevice occurred at a potential less noble than that on the open surface, and the corrosion pits formed in the crevice did not repassivate at all and continued to grow when the corrosion pits on the open surface repassivated in the same solution. (4) It is considered that the role of the coexistent anions is to prevent the formation of chloride by adsorption on the active sites of the electrode, contributing to the formation of the passive film.View full abstractDownload PDF (724K) -
Kazuo Hosokawa, Masuzo Ueda, Fumio Seki1973 Volume 37 Issue 6 Pages 611-616
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn previous work we reported a boro-carburizing method impregnating iron with boron and carbon simultaneously by dipping into a hot bath containing ferroboron and Na2CO3. B4C in the place of ferroboron, alkali metal carbonates (Na2CO3, K2CO3, Li2CO3), alkaline earth metal carbonates (SrCO3, BaCO3), and neutral salts (NaCl, BaCl2) were used in the present work. The results obtained are summarized as follows.
(1) By dipping into a hot bath containing B4C, NaCl and BaCl2, the Fe2B phase was formed on the surface and a boro-carburized layer was observed in the successive region.
(2) The surface layer consisting of Fe2B and FeB, and the boro-carburized layer were formed by dipping into a hot bath containing B4C and one of the carbonates.
Simultaneous impregnation with boron and carbon seemed to be due to the reaction expressed by the following equation between B4C and CO2 produced by the decomposition of carbonate: B4C+CO2=4 B+2 CO.View full abstractDownload PDF (704K) -
Kikuo Nakano, Toru Imura1973 Volume 37 Issue 6 Pages 617-620
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements of the Knoop hardness in the basal plane and two sorts of prismatic planes ({10\bar10}, {11\bar20}) of TiB2 single crystals grown from iron, cobalt and nickel baths were made and the following results were obtained. (1) The hardness and its anisotropy in the two kinds of prismatic planes were higher than those of the basal plane. (2) In the basal plane, when the long axis of the indentation was directed along ⟨\bar12\bar10⟩, the hardness measured was higher than that along ⟨10\bar10⟩. In the case of the crystal grown from an iron bath, the hardness difference was remarkable, and for the cases grown from cobalt and nickel baths, the difference was little or negligible. (3) As to the {10\bar10} planes, the hardness along [0001] was higher than that along ⟨1\bar210⟩. In the {11\bar20} Planes, the hardness along [0001] was higher than that along ⟨1\bar100⟩. (4) The hardness of TiB2 single crystals grown from iron, cobalt and nickel baths increased their order, when the same indentation plane and the long axis of the indentation were applied.View full abstractDownload PDF (539K) -
Ryosuke Hasegawa, Toshio Kurosawa, Tetsuo Yagihashi1973 Volume 37 Issue 6 Pages 621-627
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHydrogen reduction of WO3 and para-salt powder was studied by means of a high pressure type thermobalance in the range of 1 to 20 atm and X-ray analysis. Owing to the formation of intermediate oxides, the feature of the reduction curve was complicated. Therefore, analysis of reduction curve by the topochemical reaction model was difficult. The initiation temperature for the reduction of WO3 Was about 400°C.
The merit of pressured hydrogen was observed mainly in the reduction from WO3 to WO2 at lower temperatures such as 500°C and 600°C. At a high temperature, 700°C, the reduction rate of WO2 to W was also increased and the complete reduction time was shortened to a half of the time obtained in the atmospheric pressure.
Para-salt began to decompose from about 50°C and changed to WO3 at around 400°C. Then it was reduced to W and the merit of high pressure was found in the restraint of a sublimation loss at 800°C.
Furthermore, the change in the shape of particles with the reduction process was observed by scanning electron micrography, and the experimental results were discussed on the basis of an equilibrium diagram.View full abstractDownload PDF (771K) -
Shigeo Zaima, Akira Sugai, Kazuo Otsuka1973 Volume 37 Issue 6 Pages 628-633
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCutting-off tests on two sorts of aluminium alloy rods (2014 and 5056) are experimented in regard to the behaviour of built-up edge.
There seems to be a blank state in the cutting force during the cutting-off. That is, no cutting period is recognized in the cutting-off stage. This is due to the cause that there is a space of time before the advanced tool takes part in cutting again after the built-up edge grown and adhered on the tool tip over-cut the work surface and fell off. The space of time period is equivalent to a revolution time of work. And when the tool feed is large enough, the growth of the built-up edge is small and the blank state in cutting force is not recognized. In this experiment, the figure of the built-up edge and the depth of the over-cut are smaller in the case of 5056 cutting-off than the case of 2014 cutting-off.View full abstractDownload PDF (641K) -
Makoto Kawamoto, Toshihiro Yamada, Kunio Okabayashi1973 Volume 37 Issue 6 Pages 633-638
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAdhesive wear, which occurs in the rubbing of metals pair, is a very complicated phenomenon, since not only the flow pressure of the material (for metals, this is replaced by the indentation hardness) but also various factors are combined in a complicated way. In this work, the relation between abrasive wear, which had been proved to depend mainly on the hardness, and the Holm’s law of wear was examined by carrying out wear tests of cast iron with emery paper.
It appears that the dominating hardness of wear is not at room temperature but at the rubbing surface temperature induced by frictional heating. By expressing the hardness as a function of temperature and the temperature as a function of load and sliding speed, WL=KPeCP1⁄2V⁄Hr could be obtained theoretically from the Holm’s equation, where WL is the wear rate, P the load, V the sliding speed, Hr the hardness at room temperature, C the constant depending on the properties of material and K the constant in the Holm’s equation.
For the abrasive wear of cast iron, it was confirmed that the above equation is applicable to a considerably wide range of load and speed. Though K and C cannot be obtained theoretically and accurately at the present time, the wear rate at a given load and speed can be calculated if the two constants are determined by a small number of tests. In the repeated friction, K and C change as a function of sliding distance on account of the loss of abrasive particles on the wear track, so that the wear-distance curve is obtained by integrating the above equation along the distance. The equation did not hold at a high load and speed, at which the temperature of the rubbing surface can be considered to be very high. This cause is deduced that some factors other than the hardness also act predominantly on the wear process.View full abstractDownload PDF (557K) -
Shigeo Muromachi, Tsuneo Takahashi, Yuzo Takatsuji, Shizuo Tada1973 Volume 37 Issue 6 Pages 639-644
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn aluminum cast alloys there are so-called lautal and copper-silumin which are comparatively widely standardized within 2.0∼5.0% of copper and 3.0∼13.0% of silicon in JIS.
Accoding to the past reports, their machinability remains uncertain. This reason may be due to the difference of casting conditions, subjective matters of estimation, and the influence of impurities, etc.
In this report the tests of the specimens with minimum amounts of impurities are performed from the viewpoints of cutting resistance, tool wear, roughness of finished surface, etc.
As the results, it is evident that the addition of Si and Cu decreases the cutting resistance, and if the tool life is considered it will be better to decrease the Cu content in the specimens with a relatively large amount of Si. On the contrary, in the case of a small content of Si it will be better to increase the Cu content. The alloy containing 8.0∼10.0% of Si and 3.0% of Cu seems to be a material of excellent machinability.View full abstractDownload PDF (811K) -
Takashi Sakaki1973 Volume 37 Issue 6 Pages 645-651
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn experiment was carried out to establish an accurate method for the determination of microamounts of phosphorus in high alloy steels such as heat resisting steels and alloys containing large amounts of niobium, tantalum, titanium and other elements.
The phosphorus was separated from the various elements by coprecipitating it with beryllium hydroxide in an ammoniacal solution containing EDTA and the coprecipitated niobium, tantalum and other elements with beryllium hydroxide and phosphorus were separated from the phosphorus by extracting as cupferrates with n-bthylalcohol-chloroform mixture in a sulfuric acid solution containing hydrofluoric acid. By using jointly these separation techniques, microamounts of phosphorus could be separated accurately from large amounts of chromium, cobalt, iron, molybdenum, nickel, niobium, tantalum, titanium, tungsten, vanadium, zirconium and other elements.
The separated phosphorus was determined by the spectrophotometric method with molybdenum blue. In this method, the phosphorus was extracted as phosphomolybdic acid with n-bthylalcohol-chloroform mixture in 1.2 N sulfuric acid solution and back extracted as molybdenum blue into 10 mL or 20 mL of a reducing solution containing 1 g of stannous chloride per 100 mL of 0.6 N hydrochloric acid, and the absorbance of the obtained molybdenum blue was measured at a wavelength of 945 nm.
As a result of the experiment, the author succeeded in establishing a method in which 0.0005 to 0.02% of phosphorus in high alloy steels such as heat resisting steels and alloys containing large amounts of niobium, tantalum, titanium and other elements can precisely be measured.
The phosphorus contents in synthetic and actual samples were measured by this method with satisfactory results.View full abstractDownload PDF (561K) -
Tokio Kato, Takeo Oki1973 Volume 37 Issue 6 Pages 652-658
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTo know the anodic reaction mechnism of cuprous sulfide in sulfuric acid solution, the following experiments were made; the measurements of the electrode potentials, anodic polarization behaviours and galvanostatic polarization behaviours of the Cu2S-CuS sulfide system, and observations of the copper concentration by X-ray microanalyser (XMA) and crystal structure by X-ray reflection of the sulfide electrode surface.
(1) The electrode potentials of the Cu2S-CuS sulfide system show three characteristic values for Cu2S, Cu1.8S and CuS sulfide, respectively.
(2) Cuprous sulfide was dissolved anodically in sulfuric acid solution through the following two processes;
\phantom(1) i(i) Cu2S→CuS+Cu2++2e
\phantom(1) (ii) CuS→Cu2++S+2e.
(3) The apparent activation energy for the diffusion of copper atom in cuprous sulfide was about 3.4 kcal/mol.View full abstractDownload PDF (672K) -
Kô Soeno, Mitsuo Chigasaki1973 Volume 37 Issue 6 Pages 658-663
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitation process in ternary Al-Mg-Zn and quaternary Al-Mg-Zn-Cu alloys was investigated mainly in the temperature range of 130∼225°C with electrical resistivity measurement at liquid nitrogen temperature.
Solvus temperatures of G.P.zone are determined approximately as 135°C for Al-2.8 at% Mg-2.3 at% Zn, 190°C for Al-2.6 at% Mg-2.3 at% Zn-0.6 at% Cu and 210°C for Al-3.2 at% Mg-2.7 at% Zn-0.9 at% Cu from the relation between maximum resistivity increase in isothermal aging and the aging temperature.
Resistivity decrease in isothermal aging at 180°C was measured in detail. At on intermediate aging stage, retardation in the isothermal resistivity decrease was clearly observed especially in aging the pre-aged alloys. The retardation in resistivity decrease is associated with residual G.P.zones in aging at 180°C. Upon coarsening of precipitates in aging at 180°C, the residual G.P.zones are considered to be dissolved with resistivity decrease. Width of precipitate-free zone was decreased by G.P.zones formed during pre-aging. It was also observed that precipitation rate, measured by the changes in resistivity and proof strength, was increased by two-step aging treatments.View full abstractDownload PDF (659K) -
Yasuji Kawai, Mitsugu Anabuki1973 Volume 37 Issue 6 Pages 664-667
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSViscosity of liquid Cu-Sn alloys was measured by the rotational oscillation method. The relation between logarithmic decrements of oscillation and viscosities was determined by using water, glycerol, mercury, and liquid tin whose densities and viscosities are known accurately. Values of density of liquid alloys requisite for the determination of viscosity were taken from the literature.
Viscosity of liquid copper was expressed by the following equation:
(This article is not displayable. Please see full text pdf.)
Viscosity of liquid Cu-Sn alloys decreased with increase in tin content, but the anomaly, that is, an increase in viscosity was found over a composition range from 32 to 40% Sn. It was considered that this anomaly is due to the presence of a mixture of clusters such as Cu4Sn, Cu8Sn2, and Cu6Sn2.View full abstractDownload PDF (317K) -
Yasuji Kawai, Makoto Kishimoto, Hirohiko Tsuru1973 Volume 37 Issue 6 Pages 668-672
Published: 1973
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSurface tension and density of liquid Cu-Sn alloys were measured by the maximum bubble pressure method and also by the sessile drop method. Values of density agreed well with those obtained by previous investigators. Surface tension of liquid copper was slightly higher than values obtained by previous investigators, but that of liquid tin was nearly the same as those given in the literature.
Surface tension of liquid copper decreased remarkably by the addition of tin. The temperature coefficient of surface tension was positive over the composition range from 30 to 50% Sn and was maximum at 32% Sn. Presumably, this resulted from the dissociation of clusters in the liquid alloy with increase in temperature.View full abstractDownload PDF (359K)
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