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Volume 39, Issue 12
Displaying 1-17 of 17 articles from this issue
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Han-ryong Pak, Toshio Saburi, Soji Nenno1975 Volume 39 Issue 12 Pages 1215-1222
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn investigation of the mechanical behavior of Ni3Ge was made. Flow stress measurements were made on single crystals with several different orientations. Slip systems were determined by two-surface trace analysis, and dislocation arrangements due to deformation were observed by transmission electron microscopy. The yield stress, obtained over the temperature range −196 to 800°C, increases with increasing temperature in the temperature range where {111} slip operates (positive temperature dependence), but it decreases as {001} slip commences. Critical resolved shear stress for {111}⟨101⟩ slip is orientation-dependent in this temperature range. The positive temperature dependence is pronounced even below room temperature, and the yield stress nearly doubles as the temperature is raised from −196 to 27°C. Electron microscope observation on dislocation arrangements in the specimens deformed at −196 and 27°C has revealed that the mobility of screw dislocations decreases with increasing temperature. These observations indicate that the positive temperature dependence of the yield stress is controlled by the mobility of screw dislocations. This decrease of mobility leading to the positive temperature dependence of the yield stress can be explained by thermally activated cross slip of screw dislocations from the (111) plane to the (010) plane.View full abstractDownload PDF (1324K) -
Yutaka Nakayama, Taichiro Ito, Hiroshi Mabuchi1975 Volume 39 Issue 12 Pages 1222-1227
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCu-5.0 at%Si alloy single crystals having various orientations were tested at −196°C in compression. In this work, the characteristics of deformation twinning were investigated and compared with those of the previous works in the tensile test. The results are summarized as follows.
(1) The onset of twinning in the compressive test is characterized by a bent in the stress-strain curve and a formation of twin bands observed by optical microscopy. Also, it has been observed by transmission electron microscopy that the twin band contains many individual fine twin lamellae and the width of these lamellae are about 0.1μ.
(2) The twinning systems in the compressive test are (111)[11\bar2] and (\bar111)[\bar11\bar2], but these systems are different from that in the tensile test, namely (111)[\bar211] and (\bar1\bar11)[\bar121]; this behavior is explained by the concept of polarization of shear, i.e., unidirectionality of twinning.
(3) In the compressive test by 10% strain, the region showing twinning in the stereographic triangle is limited to the orientations near [001].
(4) The orientation dependence of the twinning in the compressive test cannot be explained in terms of the dislocation reaction proposed by Venables and Cohen et al.View full abstractDownload PDF (687K) -
Kazuo Tsumuraya, Seiichi Nishikawa1975 Volume 39 Issue 12 Pages 1228-1234
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAgeing Characteristics in a supersaturated Pb-0.038 wt%As alloy have been investigated resistometrically with particular emphasis on the quenching method, to make clear the anomalous enhancement effect of As in Pb-Sb alloys.
Three stage are found in the isochronal resistivity curves. The rate of resistivity decrease in the first stage (∼−50°C) cannot be explained by the diffusion of As atoms under the equilibrium vacancy concentration. The activation energy for migration of As atoms in this stage is found to be 0.51±0.10 eV. This is near the activation energy for migration of a vacancy in lead. It has been shown that this stage is accelerated and rate controlled by the diffusion of quenched-in excess vacancies. The second stage having activation energy 1.21±0.04 eV is the precipitation of intermediate phase. The third is the precipitation of equilibrium phase, rhombohedral arsenic, which gives the activation energy 1.18±0.07 eV. A faint resistivity increase between the second and the third in the isochronal curves is due to the reversion reaction of intermediate precipitates.
Anomalous enhancement effect in Pb-Sb alloys with small As addition may be due to the large binding energy between an As atom and a vacancy, and small As precipitates formed homogeneously with large rate in the early stage of ageing act as nuclei of Sb precipitates. The inevitability of affinity between As and Sb atoms is also discussed.View full abstractDownload PDF (629K) -
Osamu Michikami, Shoichi Yamamoto1975 Volume 39 Issue 12 Pages 1234-1243
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe surfaces of contact materials of Au, Ag, Cu and Pd were honed with alumina. An alumina particle with a diameter of the order of 40 μm composed of many corpuscles (1∼2 μm) was used. Dry honing phenomena that exert influence on contact phenomena were clarified. Physical properties of dry-honed layer such as hardness, surface roughness and microstructure were investigated. Some of the contact characteristics were studied. The experimental results can be summarized as follows.
(1) Dry honing roughens the contact surface and has the effect of surface cleaning. In the honed surface layer, the residual stress is stored and alumina corpuscles are buried.
(2) Dry honing contact shows a low and stable contact resistance in air and the contact resistance characteristic is maintained even in a corrosive gas environment. This is because that the tarnish film is broken by the roughness of the honed surface.
(3) Wear resistance and adhesion characteristics are improved by dry honing. This is largely due to the buried alumina corpuscles and the hardening of the surface layer.View full abstractDownload PDF (1011K) -
Masahiro Ashizuka, Keiz\={o} \={O}e1975 Volume 39 Issue 12 Pages 1243-1249
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrical double layer capacitance at the interface of a platinum electrode and oxide melts in the systems CaO-SiO2, CaO-SiO2-Al2O3 and CaO-Al2O3 was measured by an AC impedance method.
The results obtained are as follows:
(1) Capacitance-Potential curves (C-E curves) measured at various frequencies (0.2∼2.0 kHz) were similar to those for Na2O-SiO2 previously investigated.
(2) There were two minima and a hump on the C-E curves extrapolated to an infinite frequency.
(3) The maximum capacitance on the C-E curves increased with increasing CaO concentration and temperature.
(4) The maximum on the C-E curves for CaO-Al2O3 melts was larger than those for CaO-SiO2 and CaO-SiO2-Al2O3.
(5) The minimum capacitances extrapolated to infinite frequency increased with increasing CaO concentration and temperature, and the effect of temperature was more pronounced for basic slags.
(6) The minimum capacitance on the anodic branch was in the vicinity of 100 mV (vs Pt), indicating adsorption of oxygen ions on the surface of the Pt electrode.
(7) The span of E for adsorption or desorption of oxygen ions extended 250 to 300 mV and was independent of slag composition.View full abstractDownload PDF (562K) -
Akiyasu Yuki1975 Volume 39 Issue 12 Pages 1249-1253
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe built-up edge in cutting metals has a large effect on the surface roughness and dimensional accuracy. In drilling aluminum alloys, the built-up edge grows greatly in general, so that the behavior of built-up edge is very important for the evaluation of machinability. Most of the studies of the built-up edge have mainly been concerned with the section perpendicular to the cutting lip. In this study, the built-up edge on the profile along the lip and perpendicular to the rake surface is investigated.
The results obtained are as follows:
(1) The geometry and size of the profile of built-up edge vary depending on the kind of material, the cutting condition and the drill shape.
(2) The profile of built-up edge can be classified broadly into two types; the convex type and flat type.
(3) If a ratio of maximum thickness to the distance beeween its position and outer edge is taken in order to express the profile of the built-up edge, the correlation between the built-up edge, the chip flow angle and the surface roughness will be made clearer.View full abstractDownload PDF (463K) -
Noboru Yahata, Fusao Hayama1975 Volume 39 Issue 12 Pages 1254-1260
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study has been made of the relation between wear characteristics of annealed mild steel and the worn surface layer. Unlubricated sliding wear tests were performed at sliding speed 0.5∼5 m/sec under a contact pressure of 13 kg/cm2 in air, using a pin-on-ring machine.
The results obtained are as follows:
(1) When the sliding surface was covered with thick oxide powder, the wear rate markedly decreased. It was, however, observed that much of the oxide powder happened to be imbedded in the surface layer, so that the upper substrate could easily be torn off by friction force.
(2) The area near the sliding surface was severely deformed and showed considerably high hardness values due to work hardening or phase transformation.
(3) Although the average temperature of the sliding surface was low, viz. about 80∼180°C, the FeO oxide or a transformed phase was produced by friction heat at the real contact area (the flash temperature). Depending on the sliding speed, in particular, the transformed phase was in the form of a patch or comparatively uniform layer.
(4) The residual stress in the surface layer was exceedingly compressive at a low sliding speed, but it decreased or occasionally changed to tensile with increasing sliding speed. Therefore, no clear relation between the residual stress and the wear rate existed.View full abstractDownload PDF (961K) -
Osamu Okuno, Ishi Miura1975 Volume 39 Issue 12 Pages 1261-1266
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis investigation was concerned with the tensile strength of α-Al2O3 whisker fragments and β-SiC whisker fragments which remained after tensile testing of these whiskers. Outer surfaces and fracture surfaces of whiskers were observed by SEM. And relations between flaws and strength were discussed. The results obtained are as follows:
(1) The repeatedly tested tensile strength of α-Al2O3 whiskers and β-SiC whiskers were found to be 1.5∼4 times as high as the initial tensile strength of these whiskers.
(2) The remarkable increase of the repeatedly tested strength suggests that the stress concentration at surface flaws may cause fracture nucleation.
(3) Many types of surface flaws which may affects the strength of whisker were observed by SEM. Among these surface flaws, “step” was the highest in number.
(4) When an ideal interface between whisker and matrix can be obtained, the strength of whisker in a composite may be higher than in the air, because the stress concentration at surface flaws of whisker may be decreased in the composite.View full abstractDownload PDF (593K) -
Kiyoshi Inoue, Ky\={o}ji Tachikawa1975 Volume 39 Issue 12 Pages 1266-1273
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSuperconducting transition temperature Tc, upper critical field Hc2 and low temperature specific heat have been measured for Laves phase compounds, V2HfxZr1−x in the V-Hf-Zr ternary system. In this alloy system, the highest Hc2(4.2 K) of 240 kOe and the highest Tc of 10.1 K are achieved for the composition of V2Hf0.55Zr0.45 and V2.3Hf0.5Zr0.5, respectively. Hc2(4.2 K) of this material is higher than that of commercially available high-field superconductor, e.g., Nb3Sn and V3Ga. In addition, this material has a relatively small Vickers hardness, from 280 to 470 depending on x, and is not so mechanically brittle as other high-field superconducting compounds.
Electronic specific heat coefficient γ for V2Hf and V2Hf0.5Zr0.5 are 21.7 and 28.3 mJ/atg·K2, respectively. The large γ and spin-orbit scattering effect due to heavy hafnium atoms seem to enhance Hc2 in this material. Debye temperature θD for V2Hf and V2Hf0.5Zr0.5 are 187 K and 197 K, respectively. These low θD might cause relatively low Tc in this material, withstanding the large electron-phonon coupling. The crystal structure of V2HfxZr1−x transforms from cubic to orthorombic at a temperature Tt, ranging from 90 to 160 K. In V2HfxZr1−x, the lower Tt, the higher becomes Tc; the lattice softening associated with the lattice transformation seems to be related with the enhancement of Tc.View full abstractDownload PDF (686K) -
Kiyoshi Inoue, Ky\={o}ji Tachikawa1975 Volume 39 Issue 12 Pages 1274-1282
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSC-15 crystal-type Laves phase compounds V2HfxZr1−x was fabricated into a tape by a composite process in which the Laves phase layers were formed by the diffusion reaction between the vanadium sheath and the HfxZr1−x alloy core. The diffusion reaction and superconducting properties of the tape were studied with respect to the composition of the HfxZr1−x core and the heat treatment condition. Besides the Laves phase layers, β solid-solution phase layers are formed by the diffusion reaction. The lower limit of the β-phase formation temperature is 775°C for V/Zr and increases monotonically with x, reaching to 1225°C for V/Hf while that of the Laves phase formation temperature is about 800°C, independent on x. The diffusion rate of hafnium atoms into the Laves phase layer is larger than that of zirconium atoms.
The most suitable heating temperature for obtaining large critical current Ic is in the range from 950°C to 1050°C depending on the composition of the HfxZr1−x core. In the composition range 0.4≥x≥0.3, the composite tape shows the maximum values of superconducting transition temperature Tc, upper critical field Hc2 (4.2 K) and critical current density Jc (4.2 K, 65 kOe), which are 10.2 K, 208 kOe and 4×105 A/cm2, respectively. Ic of the composite tape, 150 μm in thickness, does not fall by winding into coils with diameters larger than 20 mm. The present study has revealed that the V/HfxZr1−x composite seems to be very promising for its practical use as a new high-field superconductor.View full abstractDownload PDF (889K) -
Kiyoshi Aoki, Osamu Izumi1975 Volume 39 Issue 12 Pages 1282-1289
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influence of deviation of composition from stoichiometry and of substitutional alloying elements on the strength of the polycrystalline intermetallic compound Ni3Al was investigated by the compression test over the range from room temperature to 1000°C. The main results obtained are as follows.
(1) The shape of the work hardening curve is observed to be linear at room temperature, and it turns out to be a parabolic one at a higher temperature.
(2) The yield stress increases almost linearly with the increase of alloying contents at room temperature, and the solution hardening ratio also increases. The ratio is higher in the order of solutes Cu, Ti, Ni, Ta and Al, successively.
(3) The positive temperature dependence of yield stress is observed from room temperature to about 600°C for all specimens and the temperature where the yield stress attains a maximum value is little changed.
(4) The temperature and composition dependence of yield stress of Ni3Al is more pronounced at the Al-richer side than at the Al-poorer side than stoichiometry.
(5) The variation of yield stress arising from deviations from the stoichiometry and the substitutional solution hardening in Ni3Al cannot be explained only in terms of a decrease of the long range order parameter or by a change of the lattice parameter.View full abstractDownload PDF (663K) -
Hakaru Masumoto, Masakatsu Hinai, Y\={u}etsu Murakami1975 Volume 39 Issue 12 Pages 1290-1293
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNi-Fe-Ta-Cr alloys were heated in hydrogen atmosphere at 1150°C for 3 hr and then cooled at rates of 0.75∼600°C/hr from a temperature above order-disorder transformation points. The highest values of 140000 in initial permeability and 599000 in maximum permeability were obtained with the alloy of 74.08%Ni, 11.26%Fe, 14.11%Ta and 0.55%Cr when cooled at the rate of 200°C/hr. The alloy exhibited an electrical resistivity of 75.6 μΩ-cm and 201 Vickers hardness. Also these high permeability Ni-Fe-Ta-Cr alloys show very low values of saturation magnetostriction constants.View full abstractDownload PDF (296K) -
Minoru Tanaka, J\={o} Yamamoto1975 Volume 39 Issue 12 Pages 1294-1301
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanical properties and structures of the two alloys (Fe-12Ni-6Mn-0.15C and Fe-12Ni-6Mn-0.15C-4Mo) after the thermomechanical treatments have been studied. The results obtained in this paper are summarized as follows:
(1) The microduplex structure of martensite containing about 30 vol% of austenite is obtained by the double rolling at 500°C, and at −75°C or −196°C after air-cooling from 1200°C.
(2) When both alloys consist of the microduplex structure of martensite containing about 30 vol% stable austenite, they show high ductility such as 190 kg/mm2 in proof strength and 45% in reduction of area.
(3) By the aging at 550°C after the double rolling at 500°C and −195°C, the alloy containing C and Mo becomes the microduplex structure of martensite with about 54 vol% stable austenite, and shows a preferable combination of strength and ductility such as 166 kg/mm2 in proof strength, 16% in elongation, 58% in reduction of area and 9 kg-m in Charpy energy (2 mm V notch).
(4) An effective improvement of ductility on Fe-12Ni-6Mn martensitic alloy can be obtained by both alloying 0.15%C and 4%Mo and thermomechanical treatment. It can be considered that this effective improvement is dependent strongly on the fine dispersed Mo-carbide and with the microduplex structure of martensite and stable austenite due to the double rolling.View full abstractDownload PDF (810K) -
Katsumi Mori, Makoto Kishimoto, Toshinori Shimose, Yasuji Kawai1975 Volume 39 Issue 12 Pages 1301-1307
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSurface tension of liquid binary and ternary iron alloys containing Cr from 0 to 40% and Ni from 0 to 100% was measured by the sessile drop method at temperatures up to 1600°C.
Surface tension of Fe-Ni alloys decreased linearly with temperature except for an alloy containing 60 at%Ni, where the temperature coefficient of surface tension was positive. Addition of Ni up to 60 at% leads to the decrease of surface tension of iron, but its further addition to the slight increase. Therefore, the surface tension isotherm has a minimum at 60 at%Ni, which tends to disappear with increase in temperature.
Surface tension of Fe-Cr and Ni-Cr alloys decreased monotonously with chromium content up to 40%. The change in surface tension of Fe-Cr alloy with composition agreed with the equation for the ideal solution derived from statistical thermodynamic consideration by Guggenheim.
Surface tension of the ternary alloys was determined mainly by the chromium content and the effect of nickel was very small.
According to the calculation by the Gibbs adsorption equation, it was found that chromium is enriched in the surface layer of the ternary alloys, but nickel which is enriched slightly in Fe-Ni binary alloys is depleted from the surface.View full abstractDownload PDF (571K) -
Teruo Kiyosawa, Katashi Masumoto, Shigehiro Isomura1975 Volume 39 Issue 12 Pages 1307-1312
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to determine the experimental conditions for vapor growth of GaxIn1−xSb (0<x<1) solid solution in an open tube system, the chemical equilibria for the GaxIn1−xSb (s)-HCl (g)-H2 (g) system at atmospheric pressure was examined regarding the chemical equilibria in the Ga-In-Sb ternary system. The dependences of the vapor phase composition on temperature, solid solution composition, mixing ratio of HCl (g)-H2 (g), and atomic ratio of (Ga+In) to Sb in the vapor phase were calculated.View full abstractDownload PDF (489K) -
Kenji Morinaga, Yukio Suginohara, Tsutomu Yanagase1975 Volume 39 Issue 12 Pages 1312-1317
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrical conductivities of CaO-SiO2-Fe2O3 and Na2O-SiO2-Fe2O3 melts were measured in order to find out the behavior of Fe2O3 in these systems. Since Fe3+ ion is the amphoterci cation, it may be assumed that Fe3+ ion in octahedral sites will contribute to the electrical conductivities of these melts, but not Fe3+ ion in tetrahedral sites.
In the Na2O-SiO2 system, the oxygen coordination number of Fe3+ ion is changed at Na2O/Fe2O3\fallingdotseq1. When the ratio of Na2O/Fe2O3 in the melt is less than unity, Fe3+ ion tends to contribute to the electrical conductivity as a network modifier. On the other hand, Fe3+ ion will give no contributions to the electrical conductivity at the composition of Na2O/Fe2O3>1. The ratio of Fe3+(oct.)/Fe3+(tetr.) also varied with the basicity of melts.View full abstractDownload PDF (467K) -
Shigeru Asano, Masuhiro Goto, Rikuro Otsuka1975 Volume 39 Issue 12 Pages 1318-1319
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (136K)
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