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Volume 41, Issue 2
Displaying 1-17 of 17 articles from this issue
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Hiroyasu Fujimori, Michio Kikuchi, Yoshihisa Obi, Tsuyoshi Masumoto1977 Volume 41 Issue 2 Pages 111-116
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAmorphous alloys of (Fe1−xCox)80P13C7 and (Fe1−xCox)75Si15B10 were prepared by rapid quenching from the melt by using two solidification techniques of centrifugal and roller types. Specimens were ribbons in form. Measurements were made of B-H hysteresis loop, effective permeability at high frequencies, longitudinal magnetostriction, electrical resistance, Vickers hardness and tensile strength.
The magnetostriction is zero at a composition near x=0.94, being positive in the range of 0≤x<0.94 and negative in the range of 1≥x>0.94. The alloy of Fe4.7Co70.3Si15B10 having a nearly zero magnetostriction exhibits the best soft magnetic properties; the coercive force is 0.006Oe and the maximum permeability is about 820×103 after annealing at 150°C in a magnetic field. In addition, this alloy has a high effective permeability at higher frequencies up to about 100 kHz, high hardness and high tensile strength.View full abstractDownload PDF (499K) -
Shinya Otsuka, Haruyoshi Tanabe, Zensaku Kozuka1977 Volume 41 Issue 2 Pages 117-123
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSLiquid Copper contained in a stabilized zirconia crucible of a very small radius was deoxidized by CO+CO2 gas and CO+H2 gas mixtures at 1150°C. The oxygen concentration at the bottom of the liquid copper column was measured continuously by the electromotive force of the following oxygen concentration cell,
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At first, the liquid copper was deoxidized much faster than one regarded as a stagnant state as soon as the gas mixture was blown up to the surface of liquid copper. After that, the retardation of deoxidation was found in a moment and the secondary deoxidation began again.
This experimental result suggested the convection in liquid copper even in the small tube which was considered to be induced by the surface tension difference.
When the CO+H2 gas mixture was used as a reducing gas, the secondary deoxidation was faster than that of free H2 gas.
By another experiment, the surface motion of liquid copper was observed directly during the deoxidation. From this observation, the convection in liquid copper during the deoxidation was found to be induced by the surface motion due to the surface tension difference.View full abstractDownload PDF (613K) -
Yoshihiko Kunieda, Takeo Oki1977 Volume 41 Issue 2 Pages 123-130
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor elucidation of the dissolution mechanism of β-ZnS, measurements of the polarization behaviours of the graphite electrode by cyclic voltammetry and of the interfacial impedances of the graphite electrode and a mixture electrode of graphite and β-ZnS under potentiostatic polarization were performed in an acidic aqueous solution at pH 1.
The experimental results obtained are as follows:
(1) At low electrode potentials (0.2∼0.702 V), the reaction of the graphite electrode under anodic polarization, is controlled by the diffusion process of the dissolution of (C-OH) species into the solution, while at high potentials (0.81∼1.09 V), it is governed by the charge-transfer of the evolution-reaction of gas (mainly CO2) and the diffusion process of it into the solution simultaneously. Moreover, at higher potentials (1.18∼1.44 V), it is controlled only by the diffusion of CO2 through the gas layer.
Under cathodic polarization, the reaction is controlled by the charge-transfer of the reduction-reaction of the dissolved oxygen and the diffusion process of it into the electrode simultaneously.
(2) The reactions of the mixture electrode of graphite and β-ZnS can be divided into the following three potential regions: the region of the reduction-reaction of the dissolved oxygen and the hydrogen-discharge reaction (H2S evolution-reaction is involved slightly), the dissolution region of β-ZnS by the galvanic reaction and the dissolution-reaction of β-ZnS with the electrolyzed oxygen.View full abstractDownload PDF (593K) -
An Investigation of Processes of Ductile Fracture Using Prestrained Tough-Pitch and Sintered CoppersKiyotsugu Ohji, Keiji Ogura, Yoshiharu Mutoh1977 Volume 41 Issue 2 Pages 130-135
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDetails of the processes of void initiation, growth and coalescence in ductile fracture were investigated by using a tough-pitch copper and a void-controlled sintered copper. The initial shape and volume fraction of voids were controlled by compressive and tensile prestraining, work hardening of the matrix being eliminated by annealing. The tensile fracture ductility of these coppers decreased with increasing volume fraction of voids which were generated by prestraining, but it was little affected by the initial shape of the voids. The work hardening of the matrix promoted void initiation and decreased the ductility. The microvoids produced by highly prestraining remarkably decreased the fracture ductility of the prestrained specimen. This result also supports the previously reported conclusion that the final stage of coalescence of voids in copper subjected to tension is triggered by the initiation of microvoids.View full abstractDownload PDF (1135K) -
Shizuo Mukae, Makoto Fujiwara, Masayuki Serino1977 Volume 41 Issue 2 Pages 136-142
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUp to the present, there are many investigations on the temperature dependences of mechanical properties of steels at low temperatures. However, the temperature dependences have been divided into three or four regions by merely thinking of the deformation mechanisms which depend on wavy slip or twinning. As a result, there are unsolved problems such as considerations of the differences in expressive equation and in strain rate and the application of dislocation theory.
In this study, the correlativity between temperature dependences on Vickers hardness, the tensile properties and the impact energy for several kinds of commercial steels was examined, and some considerations were given to the deformation mechanism in each region.
\ oindentThe results obtained are as follows:
(1) σ0.2% vs T1⁄2 curve and V* vs T1⁄2 curve consist of three straight lines whose gradients change at the temperatures TT0, TT1 and TV*0, TV*1. Each region of the three straight lines are named Regions I, II and III, respectively. Region I corresponds to the athermal deformation field, Region II to the cross slip field, and Region III to the Peierls deformation field.
(2) While, both Hv vs T1⁄2 curve and logHv vs 1⁄T curve have four straight lines, i.e., Regions, I, II, III and IV. Region IV is considered to correspond to the twinning deformation field.
(3) The correspondence between the mutation temperatures HT0 and HT1 in the logHv vs 1⁄T curve and VT1 and VT2 in the logE vs 1⁄T curve is very good for the case of 1⁄HT0 vs 1⁄VT1 and 1⁄HT1 vs 1⁄VT2 and the correspondence between the transition temperature VTrE or VTrS in the impact test and HT0 or HT1 is better at 1⁄VTrE or 1⁄VTrS vs 1⁄HT1.View full abstractDownload PDF (494K) -
Yoshiaki Iijima, Ken-ichi Hirano, Kazuo Sato1977 Volume 41 Issue 2 Pages 142-148
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInterdiffusion coefficient, \ ildeD, in Cu-Mn alloys has been determined by Matano’s method in the temperature range between 748 and 930°C for the various couples consisting of pure copper and the Cu-Mn alloy. \ ildeD increases with manganese content up to 30 at%Mn and decreases remarkably with further increase of manganese. Concentration dependence of the activation energy and the frequency factor for interdiffusion show a small peak at 20 at%Mn and a very large peak at 80 at%Mn; the former is attributed to the increase of rigidity of the alloy and the latter to the deviation from the ideal solution at respective concentration of manganese. It has been found that the Kirkendall marker moves toward the manganese-rich side and the Kirkendall voids form on the manganese side, showing that the manganese atom diffuses faster than the copper atom. From the marker shift, the intrinsic diffusion coefficients, DMn and DCu, in 29 and 77 at%Mn alloys have been determined, and the results show that the ratio of DMn⁄DCu is 1.5∼2.9.View full abstractDownload PDF (706K) -
Toshio Yamashita, Takaharu Gamo, Yoshio Moriwaki, Masataro Fukuda1977 Volume 41 Issue 2 Pages 148-154
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHydride formation of Ti-Mn binary alloys was studied between the composition limits of 33.3 at%Ti-66.7 at%Mn and 66.7 at%Ti-33.3 at%Mn, corresponding to the atomic proportions TiMn2 and Ti2Mn.
The intermetallic compound TiMn2 has a hexagonal structure of MgZn2 type known as the Laves phase, which extends over a range of composition from approximately 32 to 45 at%Ti.
In this range, TiMn2 and TiMn1.75 absorbed almost no hydrogen, but alloys containing Ti richer than TiMn1.75 did react readily with hydrogen at room temperature. TiMn1.5 has the same stucture as TiMn2, with a slight expansion of the lattice parameters, and it reacted with hydrogen to form hydride of TiMn1.5H2.14 at room temperature without any activation treatment. The relative partial molar enthalpy of hydrogen for the composition TiMn1.5H1.5 determined from the dissociation isotherms was −7.0 kcal/mol H2. The hydride of TiMn1.5 showed suitable properties as a hydrogen storage medium since it had a dissociation pressure of over 1 atm at 0°C, a maximum hydrogen content of nearly 200 cc/g at 35 atm and a hydrogen desorption ratio of about 75% against 1 atm of H2 at 20°C.View full abstractDownload PDF (662K) -
Hisashi Suzuki, Koji Hayashi, Yasunori Fuke1977 Volume 41 Issue 2 Pages 155-159
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relation between transverse-rupture strength (σm) and tensile-rupture strength (σt) in cemented carbides was studied paying attention to the microstructural defect as a fracture source. The conventional WC-10 and 20%Co alloys with a mean carbide grain size of 1.3 μm were used as specimens. Hot-isostatically pressed WC-10%Co alloy was also used. The transverse-rupture test was done according to the JIS, and the dimensions of the tensile test specimen were 4.0 mmφ in gage section and 30 mm in length.
The results obtained were as follows: (1) The ratios of \barσm⁄\barσt in this study were about 1.7 and 1.4 in conventional WC-10 and 20%Co alloys, respectively. These ratios were quantitatively explained, when the difference in dimensions of fracture sources between the two tests, the location of defects in the transverse-rupture test specimens and the overestimated value of σm (from usual beam formula) in particular in high cobalt alloys were taken into account. The ratio was confirmed to approach the value of 1.0, as the distribution of defect size within specimens became narrower. (2) For further confirmation of the above explanation, the exponent of Weibull’s equation was examined in both tests. It was found that the exponent did not generally coincide in each test, as expected from the above results. Thus, the strength of the alloy including the ratio of \barσm⁄\barσt was by no means considered to be explicable by Weibull’s theory.View full abstractDownload PDF (465K) -
Yasutoshi Kusuda, Takashi Nakamura, Tsutomu Yanagase1977 Volume 41 Issue 2 Pages 160-164
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe measurments of electrical conductivity in the BaO-SiO2-TiO2 system and the (alkali oxides or alkaline earth oxides)-SiO2-TiO2 system were conducted in order to clarify the behavior of TiO2 in melts. When the BaO/SiO2 molar ratio is constant in the BaO-SiO2-TiO2 system, the electrical conductivity tends to increase with increasing TiO2 content to a more markable extent in the acidic melt. The activation energy for the electrical conductance lies between 20 and 50 kcal/mol in the same melts.
In the melts (Li2O, Na2O or K2O):SiO2:TiO2=35:30:35, the addition of TiO2 was found to decrease the electrical conductivity. On the other hand, in the melts (CaO, SrO or EaO)-SiO2-TiO2 the electrical conductivity increased with the addition of TiO2. The results obtained support the idea presented in the previous paper that there are 6 and 4 co-ordinated Ti ions in the silicate melt and only 6 co-ordinated ions contributed to the electrical conductance. The ratio of these two types of ions depends upon the basicity of melts. When a parameter (KP) for the electrical conductivity is introduced as in the following equation, the values of electrical conductivity will be shown with a straight line as a function of KP.
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Takashi Nakamura, Tsutomu Yanagase1977 Volume 41 Issue 2 Pages 165-169
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInfra-red absorption spectra and X-ray emission spectra of Al(Kα, Kβ) in the CaO-Al2O3 and CaO-CaF2-Al2O3 systems were observed in order to investigate the ionic structure and the role of F ions in these systems. The absorption peak appears in the range of 750∼800 cm−1 in CaO-Al2O3 glasses. When the Al2O3 content increased up to the composition of CaO:Al2O3=1:1, the peak showed a higher wave number in this range, which will suggest that the wave number of the absorption peak indicates the polymerization state of aluminate anion like silicate anion. When CaF2 was added to the CaO rich glasses (CaO:Al2O3=12:5, mol ratio), the absorption spectra gave almost the same profile. On the other hand, when CaF2 was added to the glasses (CaO:Al2O3=12:10), the main absorption peak at 780 cm−1 was kept almost constant but the absorption increased in the range of 500∼600 cm−1. Accordingly, CaF2 seems to have no influence on the structure of aluminate anion in CaO rich glasses but some influence in the other glasses. This result was in good agreement with that of X-ray emission spectra of Al in this work. According to the phase diagram in CaO-CaF2-Al2O3 by A. K. Chatterjee, there appears 2 liquids in the CaF2 and Al2O3 rich region. This was confirmed by observing directly its melt heated on the Pt-filament.View full abstractDownload PDF (389K) -
Kiyoshi Aoki, Osamu Izumi1977 Volume 41 Issue 2 Pages 170-175
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCompressive and tensile tests were performed by using both single and polycrystal specimens of an intermetallic compound Ni3Al which had usually been believed to be brittle, and especially the ductility was examined by comparing the elongation of specimens through the observation of fracture surfaces. Main results obtained are summarized as follows.
(1) Polycrystal specimens homogenized after casting do not show any elongation by tension at every temperature, and the fractured surfaces exhibit an intergranular fracture mode. On the other hand, compressive plastic deformation is possible to some extent, though intergranular fractures are also accompanied.
(2) Single crystal specimens show about 100 per cent elongation at and below room temperature. At higher temperature, the elongations markedly decrease with increasing temperature and attain minimum values at the peak temperature of yield stress. Fracture modes are all ductile ones, showing dimple patterns observable at a large magnification.
(3) Polycrystal specimens, which were obtained by recrystallization annealing of the cold rolled single crystals, show about 15 per cent elongation even at room temperature. Fractography observation shows the transgranular fracture as well as the intergranular one. Thus, the lack of ductility in Ni3Al polycrystals seems to be caused mainly by a segregation of impurity atoms to the grain boundary.View full abstractDownload PDF (808K) -
Kazuo Suzuki, Tetuo Fujiwara, Satoru Mito1977 Volume 41 Issue 2 Pages 175-182
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSErosion resistance to cavitation of chromium carbide base sintered alloys, i.e. Cr3C2+15%Ni(conventional) and Cr3C2+40%WC+15%Ni(newly developed), are evaluated by means of the magnetostrictive accelerated cavitation machine under the following experimental conditions; 6500 Hz frequency, 100 micron-m amplitude, pure, water testing liquid at 25°C and 180 min overall testing time. Erosion weight losses of specimens are measured with high accuracy at 30 min intervals. STELLITE® alloys are also used and evaluated under the same conditions.
Erosion surface morphologies on the test faces after the cavitation test are examined by means of optical and scanning electron microscopy. The erosion process of those sintered alloys is discussed with respect to the fatigue strength of pure nickel.
\ oindentResults obtained are summarized as follows:
(1) Erosion resistance of chromium carbide sintered alloys is 2 to 4 times superior to those of STELLITE alloys, which previously had the best erosion resistance.
(2) Erosion by cavitation starts at the carbide/nickel interfaces and selective attack of the nickel phase occurred.
(3) Calculations of the stresses required to cause fatigue fracture of the nickel phase during the cavitation test are in good agreement with the observed erosion morphologies.View full abstractDownload PDF (1246K) -
Shiomi Kikuchi, Jun Shimizu, Masao Adachi1977 Volume 41 Issue 2 Pages 182-187
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCopper-2.5 at%Al alloy single crystals oriented for a single slip system were deformed in tension at 600 and 700°C. In the later stage of deformation, the condition of steady state deformation was satisfied; namely the specimens have been deformed at a constant stress, independent of strain. In this steady state deformation stage, the internal stress and the effective stress were determined by the stress dip test. The dislocation substructure formed in this stage were observed by the etch pit technique. The results obtained are as follows:
(1) The tensile axis rotated into the direction predicted by the single glide on the (111)[\bar101] slip system. When the tensile axis approached the [001]-[\bar111] symmetry line, the steady state deformation was observed.
(2) The strain rate is proportional to the nth power of the steady state stress and the n value is about 5.
(3) The ratio of the internal stress to the applied stress is 0.6∼0.9 and depends on the applied stress. The effective stress increases with the applied stress.
(4) The parameter m* describing the effective stress sensitivity of dislocation glide velocity was estimated assuming the mobile dislocation density to be proportional to the square of the applied stress and the m* value was found to be 1.1.
(5) The subgrains elongating in the [1\bar21] direction are found on the (111) plane. On the (1\bar11) plane the rows of dislocations are found along the direction roughly parallel to the trace of the primary slip plane, and the high dislocation density regions, approximately perpendicular to the slip trace, are observed.View full abstractDownload PDF (582K) -
Tadashi Nishihara, Kazutomo Asami, Nobuhiro Iguchi1977 Volume 41 Issue 2 Pages 188-193
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe transformation superplastic behavior in commercial pure iron, hypoeutectoid steel (SS 41) and eutectoid steel (SK 5) has been examined, using an originally desinged differential type apparatus for measuring dynamic superplasticity. Strain rates in tension and torsion are measured and analysed with special attention to the principal stresses.
The main results obtained are as follows:
(1) The transformation strain of all the materials mentioned above varies linearly accompanying an increase of the applied stress at the stage of the lower stress level, and a linear relation-ship between the applied stress and the maximum strain rate was observed.
(2) For the materials under the transformation superplastic deformation, the three times-law of viscosity, λ=3η, could be applied to the relation between the normal viscosity λ and the coefficiency of viscosity η.
(3) When defining the effective stress \barσ and strain rate \bar\dotε like \barσ=3τ and \bar\dotε=\dotγ⁄3 respectively, where τ is the shear stress and \dotγ is the shear strain rate, the experimental data for two different types of the strain of tension and torsion due to the transformation superplastic flow can be explained by a unified curve.View full abstractDownload PDF (454K) -
Noboru Yahata, Noboru Hayami, Fusao Hayama1977 Volume 41 Issue 2 Pages 194-199
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe properties, characteristics and the mechanism of formation of the continuous hard layers which arise on all the friction surfaces of carbon steels under the unlubricated sliding condition in air, have been investigated by X-ray diffraction, XMA and electron microscopy.
It is seen that (1) the hardness and crystal structure of the continuous hard layer generated under the same sliding condition are dependent on the carbon content as in the case of normal quenching, and (2) their changes with the tempering temperature are nearly similar to those tempered for the conventional martensitic structure.View full abstractDownload PDF (969K) -
Hakaru Masumoto, Showhachi Sawaya, Michio Kikuchi1977 Volume 41 Issue 2 Pages 199-202
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe thermal expansion, Young’s modulus, magnetic susceptibility and electrical resistivity at −150∼500°C, and the hardness and density at room temperature have been measured with annealed Mn-Pt alloys. It has been found that Mn-10.05∼40.21%Pt alloys slow cooled after heating at 1100°C for 4 hr have distinct anomalies near the antiferromagnetic Néel point in the Young’s modulus vs temperature curves. The temperature coefficient of Young’s modulus at room temperature vs composition curve exhibits a large positive maximum at a concentration of 30.10%Pt, thus revealing the Elinvar property in this alloy system.View full abstractDownload PDF (300K) -
Katunori Abe, Hideo Yoshinaga, Shotaro Morozumi1977 Volume 41 Issue 2 Pages 202-210
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPolycrystals of V-5.0 at%Fe, which is one of the typical substitutionally solution-hardened bcc alloys, are deformed in tension over a temperature range from 1000 (0.60Tm) to 1500°C (0.84Tm) and at strain rates of 3.3×10−5, 3.3×10−4 and 3.3×10−3/sec. In this alloy is also observed a kind of work softening phenomenon, which has been found in various substitutionally solution-hardened fcc alloys. Under the conditions where this type of work softening is observed, the strain rate is represented by the relationship of \dotε=Bσnexp(−Q⁄kT), where n=4.1∼4.3 and Q=4.5∼5.5 eV.
Characteristics of the work softening phenomenon can be interpreted in terms of a deformation mechanism controlled by the dragging of solute atmosphere for dislocation motion. The results of abrupt change tests in strain rate are examined on the basis of the mechanisms, and it is concluded that the steady state deformation in this alloy is not determined by the criterion of the minimum flow stress. Conditions of reappearance of work softening in the strain rate change and unloading tests show that in some cases dynamic recovery exceeds static recovery.View full abstractDownload PDF (757K)
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