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Volume 46, Issue 4
Displaying 1-17 of 17 articles from this issue
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Hiroaki Wada, Koshiro Sakamoto1982 Volume 46 Issue 4 Pages 343-352
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has not yet been clear whether or not hydrogen hardens iron. In the present work, high purity iron single crystal specimens were used in order to clarify the effect of hydrogen on the mechanical properties of iron.
When hydrogen was electrolytically introduced into the specimens during plastic deformation at 195 K, the flow stress was considerably decreased. On the other hand, it was increased when hydrogen was introduced in an unloaded state. The amount of the decrease in flow stress decreased with increasing deformation temperature. The flow stress at 300 K was increased by the hydrogen charging during the plastic deformation.
The mobility of screw dislocations as well as that of edge dislocations in iron was found to be decreased by the presence of hydrogen atoms. It is likely that the remarkable decrease in the flow stress at 195 K is due mainly to the easy motin of edge dislocations generated at the specimen surface with the aid of hydrogen charged during the plastic deformation.View full abstractDownload PDF (946K) -
Masahisa Otsuka, Akira Nozue, Ryo Horiuchi1982 Volume 46 Issue 4 Pages 353-362
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe high temperature creep properties of Al-Be alloys strengthened by dispersed spherical beryllium particles have been investigated over the temperature range 0.51∼0.69Tm (Tm: the absolute melting temperature of the matrix) and the stress range 10−4∼10−3E (E: the Young’s modulus). The work hardening type of transient creep stage was observed prior to the steady-state creep. The steady-state creep rate, \dotεs, is related to the stress and temperature by
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\ oindentHere both the stress exponent, n (9∼10), and the activation energy for creep, Qc (138∼146 kJ/mol), are independent of stress, temperature and interparticle spacing. The observed value of Qc are close to those for creep and volume self-diffusion of the matrix material. A(λ) depends on the interparticle spacing, λ. In the alloys with samll λ, the distribution of dislocations in the steady-state creep are considerably uniform, and A(λ) is roughly proportional to λ8. In the alloys with large λ, subboundaries are formed though the dislocation density is fairly high within the subgrains, and the dependence of A(λ) on λ decreases.View full abstractDownload PDF (1635K) -
Masahisa Otsuka, Akira Nozue, Ryo Horiuchi1982 Volume 46 Issue 4 Pages 362-368
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWork hardening and recovery during high temperature creep of aluminum strengthened by dispersed beryllium particles have been investigated by means of the stress relaxation method. It was found that the proportion of the internal stress to the flow stress is nearly 100 percent and hence that the deformation is governed by a recovery process. Under the chosen condition of stress and temperature (10−4≤σ⁄E≤10−3, 0.51≤Tm⁄T≤0.69), the work hardening rate, h, showed no dependence on temperature and increased only slightly with an increase in stress. The recovery rate, r, is related to stress and temperature by
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\ oindentHere the stress exponent, nr (9.5∼10.0), is close to that for the steady-state creep rate and the activation energy for recovery, Qr (138∼152 kJ/mol), is in agreement with that for volume self-diffusion in pure aluminum. The results are in contrast to those reported for pure aluminum in which h depends both on stress and temperature and the temperature dependence of r does not agree with that of volume self-diffusion, suggesting that the recovery in Al-Be alloys may be controlled by a unique thermally activated process. It is also shown that the effect of interparticle spacing on the work hardening rate is much smaller than that on the recovery rate, and hence that the increase in creep strength is brought about by the decrease in the recovery rate.View full abstractDownload PDF (555K) -
Shigeo Sumita, Ken-ji Morinaga, Tsutomu Yanagase1982 Volume 46 Issue 4 Pages 369-373
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe solubility of CO2 in Na2O-Fe2O3 and CaO-Fe2O3 systems and its effect on the viscosity have been measured to elucidate the behavior of CO2 in these melts. The quantitative analysis of CO2 content by the use of infra-red absorption spectra has been proposed for the slag systems. The solubility of CO2 in the CaO-Fe2O3 system and the silicate melt is less than 1 mol%CO2, while in the Na2O-Fe2O3 system it is 5-20 mol%CO2 due to the strong basicity of the melts. The effect of CO2 on the viscosity of Na2O-Fe2O3 system is almost the same as that of SiO2, which indicates that the constitution of CO2 in Na2O-Fe2O3 system can be assumed to be of a complex anion type species with a unit form of CO32− such as SiO44− in silicates.View full abstractDownload PDF (370K) -
Tatsuhiko Ejima, Kazuhiko Takei1982 Volume 46 Issue 4 Pages 373-379
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe surface tension of MgCl2-LiCl and MgCl2-CsCl binary melts has been measured by means of the maximum bubble pressure method over the temperature range from liquidus to about 1200 K. Results obtained are summarized as follows:
(1) For both systems, the surface tension shows an approximately linear decrease with increasing temperature at each composition. The surface tension and its temperature coefficient increase as the content of LiCl or CsCl in the melt increases.
(2) Comparing the surface enthalpy per unit area and the surface entropy per unit area of these binary melts with those of other alkari metal chlorides, it is found that these composition dependences are classified into two groups. One is that to which the LiCl or NaCl containing melt belongs, and the other is that to which the KCl, RbCl or CsCl containing melt belongs. In the latter melt, the smaller the cation radious of the added salt is, the more the variation becomes conspicuous.
(3) The excess surface tension calculated shows a large negative value over the entire composition range of the MgCl2-LiCl binary system due to the enrichment of MgCl2 in the surface layer.
(4) The excess surface tension of the MgCl2-CsCl binary melt shows an anomalous change with composition as compared with the MgCl2-LiCl binary system. This anomaly is explained by the formation of MgCl42− complex ion in the melt and the application of the adsorption theory.View full abstractDownload PDF (506K) -
Toshihei Misawa, Hideo Sugawara, Sumio Ikeishi, Shoichi Kitamura1982 Volume 46 Issue 4 Pages 380-386
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor a better understanding of an active surface for hydriding of hydrogen storage material, a study was made on CaNi5 which readily forms metal hydride under an ordinary pressure of hydrogen at room temperature. Bulk CaNi5 easily disintegrates into powder having freshly broken surfaces with hydrogen absorption. Exoelectron emission was measured at room temperature during the disintegration process under a flowing hydrogen of 0.1 MPa, and the effects of flowing gaseous species, applied potential and gas flow rate on the emission were investigated.
The optically stimulated exoelectron emission (OSEE) was caused by the appearance of fresh surfaces in CaNi5. A remarkably large emission current was observed in Ar atmosphere, whereas in H2, N2, He and O2 atmospheres a small current was measured since the emission from fresh surfaces was inhibited by these gases. The decay curves of OSEE followed the logarithmic law, and a larger emission current in Ar continued for a long period compared with the emission in H2. The substitution peaks of H2-Ar in OSEE appeared accompanying a gas exchange between H2 and Ar, and the quantity of electricity in these peaks increased with decreasing gas flow rate. The OSEE behavior obtained was discussed on the basis of adsorption of gaseous species on the fresh metallic surfaces.View full abstractDownload PDF (867K) -
Hiroyuki Kaneko, Hiroyuki Kamata1982 Volume 46 Issue 4 Pages 387-393
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPotential profiles in solutions adjacent to rotating rod surfaces of two specimens, a copper partly electroplated with zinc and a commercial mild steel, were measured by using a scanning probe method and displayed on an oscilloscope screen. Effects, especially, of the rotational speed of the specimens and of the distance between the specimens and Luggin capillaries on the potential distribution were investigated and an adequate experimental condition on measuring the potential distribution was determined. Corroding and noncorroding sites on a specimen corresponded well to crests and troughs on a topographic map of electric potential, respectively. In addition, from the potential distribution measured immediately after the immersion of the specimen, corrodible sites and their corrosion processes can be predicted clearly. This shows that mapping the potential distribution on the specimen with time is a very promising technique to detect the formation and promotion of local corrosion cells.View full abstractDownload PDF (856K) -
Katsuyuki Takahashi, Haruno Okochi, Shinji Itoh, Emiko Sudo1982 Volume 46 Issue 4 Pages 394-400
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe emission spectrochemical analysis of nickel-base alloys and heat resisting steels by the fixed time integration methed has been developed. Nickel contents of 9 to 76% in the samples were examined in this study. For such samples, the internal standard methed was inadequate, while the fixed time integration method gave good accuracy in the determination of minor elements in these samples. Elements analysed were C, P, S, B, Si, Ta, Co, Fe, Mn, Nb, Cu, Ti, Zr and Al.
At first, ternary alloys containing a constant amount of cobalt (0.5, 1.0, 3.0, 6.0, 10.0, or 20.0%) with changing amounts of nickel and iron were prepared in order to examine the effect of nickel and iron content on the determination of these elements. It was found that the samples should be classified to two groups according to the nickel content, that is one group corresponding to 9-60% nickel and the other to 60-76%, and calibration curves had to be made separately. The equations of calibration curves were given in the regression lines of the first order in the determination of minor elements. For correcting the effect of neighbouring lines, coefficients of correction were derived by the multiple regression analysis.
The relation between the sensitivity of analysis and the coefficient of correction was examined. As the sensitivity, the gradient of calibration curves was chosen, and it was observed that there was a linear correlation between the gradient and the partial regression coefficient. After all, the relation of hyperbola was concluded to exist between the gradient and the coefficient of correction in the determination of most elements.
The gradients of calibration curves in the two groups were almost the same, but the gradients of the group containing more amount of nickel were a little larger than those of the other.View full abstractDownload PDF (452K) -
Kazuyoshi Kamachi1982 Volume 46 Issue 4 Pages 401-406
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSince austenitic stainless steels have some useful properties for medical instruments, such as high corrosion resistance, high strength and high elasticity, they are used as needles for acupancture and anesthesia. The failure of the needles, however, have been reported to occur during medical treatments. This becomes a serious problem for both a doctor and a patient.
Causes of the failure have been studied in the present paper and the following conclusion has been derived; In case in which the needle is used as an anode, the failure occurs due to pitting corrosion, whereas, in case in which it is used as a cathode, embrittlement due to hydride formation occurs.View full abstractDownload PDF (781K) -
Hakaru Masumoto, Showhachi Sawaya, Michio Kikuchi1982 Volume 46 Issue 4 Pages 407-412
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements of Young’s modulus at 150-700 K, and thermal expansion, hardness and tensile strength at room temperature were carried out for Mn-Cu-Ti and Mn-Cu-Zr alloys subjected to various heat treatments and cold-working. Young’s medulus vs temperature curves of annealed ternary alloys in these two systems have distinct minimum and maximum, indicating the existence of the fct α\ ightleftarrowsfcc γ phase transformation. The antiferromagnetic\ ightleftarrowsparamagnetic transition occurs near the phase transformation temperature. The elinvar properties appear around the temperatures showing a minimum or a maximum of Young’s modulus. The temperature coefficient of Young’s modulus at room temperature for the ternary alloys are affected by annealing, cold-working and reheating after cold-working or controlling the alloy composition. Young’s modulus and hardness of Mn-Cu binary alloys increase with increase of the alloying element such as Ti or Zr. The tensile strength shows a maximum at 3-4% of Ti or Zr, and it decreases gradually with increase of the alloying elements. These ternary elinvar alloys “MANGALOY” have no ageing effect. Therefore, they are considered to be excellently suitable for the materials of precision instruments.View full abstractDownload PDF (465K) -
Yoshiaki Tanaka, Y\={u}ji Yoshida, Toshihisa Asano, Ky\={o}ji Tachikaw ...1982 Volume 46 Issue 4 Pages 413-419
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of gallium and magnesium additions on the microstructure of composite-processed V3Ga tapes have been studied. V3Ga tape specimens were prepared by fabrication and heat-treatment of composites consisting of a V or V-Ga alloy core and a Cu-Ga or Cu-Ga-Mg alloy matrix. Additions of gallium to the vanadium core and magnesium to the Cu-Ga alloy matrix enhanced the growth rate of V3Ga layer, and the addition of magnesium was especially effective. The simultaneous addition of gallium and magnesium led to the largest growth rate, which was about twice as large as that of the pure V3Ga composite. The grain size of V3Ga became slightly finer with increasing gallium concentration in the V-Ga alloy core. A considerable change in the microstructure was observed for the addition of magnesium to the Cu-Ga alloy matrix. The magnesium addition produced appreciably finer and more equiaxed V3Ga grains. The enhanced growth rate of V3Ga layer caused by the magnesium addition could be attributed to an increase in the gallium diffusion rate through the V3Ga/Cu-Ga alloy boundary. In the present study, the V3Ga microstructure with respect to the distribution of magnesium in the V3Ga layer and the heat-treatment condition has also been examined. Furthermore, 19 core-composites of V-6 at%Ga core/Cu-19 at%Ga-0.5 at%Mg matrix were fabricated to thin wires by ordinary extrusion and drawing techniques, demonstrating the feasibility of multifilamentary-type wire fabrication.View full abstractDownload PDF (734K) -
Yoshiaki Tanaka, Y\={u}ji Yoshida, Toshihisa Asano, Ky\={o}ji Tachikaw ...1982 Volume 46 Issue 4 Pages 420-426
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of gallium and magnesium additions on the superconducting critical temperature, Tc, the upper critical magnetic field, Hc2, and the critical current density, Jc, of the composite processed V3Ga have been studied. Specimens were prepared by fabricating a composite consisting of a V-Ga alloy core and a Cu-Ga-Mg alloy matrix into tapes, and by reacting them to form V3Ga layers. The addition of 3 and 6 at%Ga to the core and that of 0.5 at%Mg to the matrix raise Tc by 0.1-0.2 K. The simultaneous addition of gallium and magnesium increases Tc by 0.2-0.3 K; the highest Tc obtained is 15.0 K. The addition of gallium to the core increases Hc2 by 1-2T. An Hc2 exceeding 22T has been obtained at 4.2 K by the simultaneous addition of gallium and magnesium. The improvement in Hc2 can primarily be attributed to the increase in Tc by the addition of these elements. Jc′s are strongly dependent on the microstructure of V3Ga which is varied by the additional element and the heat treatment condition. The magnesium addition makes V3Ga grains much finer. This grain refinement increases the flux pinning center density and produces high Jc′s. In the V-(3-6) Ga/Cu-19Ga-0.5Mg specimens high Jc values are obtained in the entire magnetic field range; Jc′s exceeding 1×109 A/m2 have been obtained at 4.2 K and 20 T. The present study reveals that the fabrication of multifilamentary V3Ga wires with excellent stability and high-field performance can be expected by the simultaneous addition of gallium and magnesium.View full abstractDownload PDF (577K) -
Kozo Osamura, Osamu Komura, Takashi Yamamoto, Tetsuro Atsumi, Yotaro M ...1982 Volume 46 Issue 4 Pages 427-432
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe early stage of precipitation in a Ni-13 at%Al alloy was investigated by means of field ion microscopy (FIM) as well as transmission electron microscopy (TEM) and the small angle X-ray scattering (XSAS) technique. Fine γ′ precipitates with L12 crystal structure could be observed by using FIM. γ′ precipitates appeared even at the as-quenched state, and an average diameter of these precipitates was 3.3 nm. During the isothermal ageing at 823 K, their particle size increased and the interparticle distance also extended gradually with ageing time. After over 6 ks ageing, some precipitates showed a regular array in the {100} lattice plane and partially had a modulated structure accompanied with a shape change from ellipsoid to cuboid. TEM observation and XSAS measurements supported strongly the FIM results mentioned above. Especially the average radii of γ′ precipitates observed by FIM were in good agreement with Guinier ones obtained from the XSAS measurements.View full abstractDownload PDF (499K) -
Toshiro Kobayashi, Hiroshi Tachibana, Wataru Yagi, Yoshisada Ueda1982 Volume 46 Issue 4 Pages 433-440
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffect of the heat treatment condition in the QLT treatment on the strengthening and toughening of 13%Cr stainless steel was studied, and the mechanism of the toughening by the quenching from (α+γ) range, i.e. the treatment (L) was considered. Samples were heat-treated by various austenitizing conditions and L treatment conditions, and the V-notched Charpy impact test and the dynamic fracture toughness test with various notch root radii were performed.
It was shown that the QLT treatment improved the toughness in the V-notched Charpy test independently of the austenitizing and L treatment conditions. But, this improvement was not always observed in the dynamic fracture toughness test.
It was also observed that the effect of notch root radius on the fracture toughness was different between the quenched-and-tempered and the QLT specimens. It was conjectured from these results that evaluation of the toughness was very difficult and that the toughness both in Charpy test and in the fracture toughness test had to be considered for the determination of the most suitable L treatment condition.View full abstractDownload PDF (812K) -
Zhong da Yin, Hajime Suto1982 Volume 46 Issue 4 Pages 441-445
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFatigue properties of 3.5 GPa-grade maraging steels (8%Ni, 18 or 20%Co, 14 or 12%Mo) with or without nitriding were investigated. Data of specimens without nitriding were very scattered. When the age-hardened alloys were nitrided for 10 to 15 min at 500°C in NH3, mean values of fatigue strength were increased and the scatter bands were shrunk. After excess nitriding, the surface hardness was decreased and the specimens were embrittled. The role of non-metallic inclusions as sources of fatigue crack may be very important and clean materials were expected.View full abstractDownload PDF (446K) -
Yonosuke Murayama, Yoshihiko Suzuki, Muneaki Shimura1982 Volume 46 Issue 4 Pages 446-452
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTi-6Al-4V alloy sheets with the basal plane texture show the “texture hardening”. The multidirectional rolling process in the α+β field has so far been proposed to cause the basal plane texture. In the present investigation, the unidirectional rolling with both dentate roll and conventional smooth roll was carried out to cause the basal plane texture. This process was able to produce the sheets showing the “texture hardening”.
In order to remove the effect of prior texture, the specimens were vacuum annealed for 1.2 ks (20 min) at 1303 K (1030°C) before rolling, and then the conventional unidirectional rolling, the cross rolling and two types, A and B (cf. Fig. 1), of the dentate rolling were carried out. The rolling temperatures were 823 K (550°C), 923 K (650°C), 1023 K (750°C) and 1173 K (900°C). In all cases, the total reduction of rolling was about 82%. After rolling, the specimens were vacuum annealed for 7.2 ks (2 h) at 973 K (700°C). The texture development in such sheets was evaluated by the (0002) plane pole figure, and the mechanical properties under biaxial stresses were deduced by uniaxial tensile tests, knoop hardness tests and through-thickness compression tests.
The following results were obtained
(1) It was recognized that the sheets by the dentate rolling had the tendency of accumulation of basal pole in the sheet normal direction. This effect was remarkable in the low temperature range.
(2) The sheets by the dentate rolling showed the higher “texture hardening” and the smaller anisotropy in the sheet plane than those by the conventional rolling.
(3) In the present experiment, the sheets by the dentate rolling type A showed the higher “texture hardening” than that by type B, and the “texture hardening” of the sheets by type A was close to that by the cross rolling.View full abstractDownload PDF (593K) -
Shigeo Zaima, Yuzo Takatsuji, Shigeru Yamada1982 Volume 46 Issue 4 Pages 452-458
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAl-Si cast alloys have been dry cut with five sorts of commercial carbide tools, i.e. P10, P20, M20, K10 and K20 tool, and the adaptability of the tools has been examined. The results are as follows:
Difference in the cutting resistance of the F material between the tool materials is not remarkable, but the cutting resistance of the T6 material by K classified tools is smaller than that by other tools. When the flank wear was taken as a standard, the tool wear became smaller in the order P10, P20, M20, K10 and K20. The tool wear of the K10 tool is smaller than that of K20 among the F materials, but among the T6 materials, the K20 tools are better. The reason why the tool wear of the K classified tools is smaller than that of the P classified tool, is probably that Ti existing in the P classified tools has a strong affinity with Al and Si and has a tendency to combine with Mg existing in the works, resulting in the promotion of the tool wear.View full abstractDownload PDF (744K)
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