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Volume 42, Issue 3
Displaying 1-17 of 17 articles from this issue
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Tadashi Momono, Katsuya Ikawa1978 Volume 42 Issue 3 Pages 211-217
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs fusion welding is liable to accompany changes in microscopic structure and mechanical properties of the weldment, solid phase welding, especially so-called diffusion bonding with a smaller plastic deformation, has received increasing attention recently.
The object of this study is to clarify the factors that govern the bond strength and the bonding process by investigating the behaviors of the solid phase-bonded interface, including the diffusion bonding process, under the various welding conditions.
The main results obtained were as follows:
(1) The bond strength of polycrystalline copper increased with an increase in the areal fraction of welding (F) which was determined by the welding pressure, temperature and time.
(2) The F value depended also upon the initial roughness of the bonding surface and the dependency was estimated by the sintering mechanism of metal powders.
(3) Disappearance or migration of the bonded interface was not observed in as-welded conditions, but the fully bonded strength was achieved in this state. The interface changes were observed firstly after the prolonged post-weld heating.
(4) Increase of the areal fraction of welding F was detected by the electric resistance measurement of the weldment.
(5) When the direction of welding pressure was near the [110] orientation of the single-crystal specimens and the easy sliding range was large, the more compact impingement and bonding was obtained, and the interface migration by post-weld heating was accelerated.View full abstractDownload PDF (923K) -
Fumihiko Ishida, Keisuke Matsuura, Toshio Doi1978 Volume 42 Issue 3 Pages 217-224
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitation process of Nb-60 at%Ti alloy aged at 550 and 350°C was examined by means of transmission electron microscopy. The experimental results obtained are as follows:
(1) On aging at 550°C after solution-treatment, a transition phase t is formed during the β→α+β transformation. The t phase is disc-shaped with habit planes parallel to {100}β and is coherent with the matrix.
(2) On aging at 550°C for a time as long as 1800 h after solution-treatment, an equilibrium phase α precipitates. The α phase is rod-shaped with habit planes parallel to {111}β. The α phase takes a hexagonal closed-packed structure with lattice parameters a=0.296 and c=0.471 nm and has the orientation relashionships (0001)α\varparallel(1\bar10)β and [11\bar20]β\varparallel[111]β.
(3) On aging at 550°C after cold-rolling, the α phase precipitates without the t phase formation.
(4) On aging at 350°C, a transition phase ω precipitates. The ω phase takes a hexagonal structure with lattice parameters a=0.463 and c=0.284 nm and has the orientation relation-ships (\bar2110)ω\varparallel(1\bar10)β and [0001]ω\varparallel[111]β.View full abstractDownload PDF (1039K) -
Kazuo Yasue, Mineo Kosaka, Mitsuo Isotani, Yasuhiko Kondo1978 Volume 42 Issue 3 Pages 225-231
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements on the thermal diffusivity of cast irons were carried out using a method, in which the surface of cylindrical specimen was heated at the constant rate in an infra-red image furnace and the temperature difference in the radial directions of specimen was measured by seathed thermocouples.
The thermal conductivity of the specimen calculated from the thermal diffusivity measured from room temperature to 873 K showed the nearly constant values described as follows:
(This article is not displayable. Please see full text pdf.)
\ oindentThe value for flaky graphite cast iron decreased from 4.6×10 to 3.3×10 W/K·m with increasing temperature.
Experimental values of thermal conductivity were discussed with respect to the chemical compositions of matrix and the morphology of graphite in the cast irons.View full abstractDownload PDF (826K) -
Kazuhiro Hara, Kunito Okamoto, Toru Shigeoka, Hiroshi Fujiwara1978 Volume 42 Issue 3 Pages 232-240
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe preferred orientation or the textures of Fe films grown under various incidence angles of the vapor beam have been investigated in order to obtain information about the mechanism of the texture formation. The texture was determined by plotting pole figures, the intensities of which were obtained by means of the X-ray Schulz method.
Two experimental results which may give the pertinent suggestion to the texture formation mechanism are as follows:
(1) The top of a columnar grain appearing on the film surface is surrounded by the {110} planes, but these planes scarcely direct toward the vapor beam direction. This result leads to a conclusion that the sticking probability α of the vapor beam on the {110} planes can be expressed as α=x+(1−x)sin2θ, where θ is the angle between the vapor beam direction and the direction normal to the {110} planes, and x varies from 0 to 1. According to this equation, a calculation has been made to obtain the normal component of the growth rate of the {110} planes to the substrate, on which the shadowing effect is appreciable. (2) The characteristic textures of the oblique incidence films have [100] and [111] as the texture axes and the angle between them is 35°, irrespective of the incidence angle. The results have been explained quantitatively by using the growth rate estimated in a range of x from 0.2 to 0.4 and by taking into account the mechanism of the stepwise structure formation observed on the {110} planes, which might result from the movement of atoms arriving successively at the crystal surface.View full abstractDownload PDF (722K) -
Kozo Kitada, Fumiyoshi Miyashita, Giroku Miyatani, Toshio Miyake, Tuyo ...1978 Volume 42 Issue 3 Pages 240-249
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present studies were concerned with the processes of carbothermic reduction of chromium oxide to metallic chromium and the effect of additions of various oxides such as Al2O3, SiO2, MgO, and CaO on the formation of chromium.
The experimental results obtained were as follows:
(1) The progress of the reduction process (reaction) was determined by the increase in the pressure in the reaction tube. The pressure change was independent of the kind of oxides added. As the number of the added oxides increased, the temperature of reaction became higher.
(2) The system consisting of more than one additive oxide exhibited two peaks in the pressure-time curves, different both in height and in width. The result showed that each process of oxide reduction was thought to be very active.
(3) The vaporization of metallic chromium was observed in the system containing no additives, which was particulaly remarkable in the system of Fe2O3 addition.
(4) It was recognized that even a very small quantity of oxides added had a marked influence on the formation of chromium by the carbo-thermic reduction of chromium oxide, and the addition of Fe2O3 only promoted the formation of chromium.
(5) The formation of metallic chromium was strongly influenced by the quantity of SiO2 or MgO added.
MgO retarded the formation of chromium in this reaction when the quantity of added MgO was smaller than that of MgO contained in chromite.View full abstractDownload PDF (765K) -
Nobuyuki Mori, Mikio Uchiyama, Keisaku \={O}gi, Kimio Matsuda1978 Volume 42 Issue 3 Pages 249-255
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn this paper, the influence of the flow velocity of bulk liquid on structures and segregations of Al-5.5%Cu and Al-14%Mg alloys were investigated. The cylindrical specimens were vertically solidified under controlled freezing conditions in a rotating electromagnetic field. The magnetic field caused bulk liquid to flow round, and the flow velocity (U) was changed within the range of 0∼20 cm/s by varying the voltage on the electromagnetic stirring device.
Specimens solidified under the temperature gradient more than 10°C/cm were composed of only columnar crystals independent of U. At a smaller temperature gradient of 3°C/cm, the equiaxed crystals appeared on the upper part of the specimens and the amount became larger with increasing U. The flow refined crystal grains and made the columnar crystals tilt to the upstream. The angle (θ) between the direction of columnar crystals and that of the thermal flow was expressed as follows: θ=a+blogU+clogR, where U was the flow velocity, R was the solidification rate, a, b, c were experimental constants depending on the species of solute and the temperature gradient.
In all specimens, normal segregation appeared as macrosegregation. As far as the specimens with the columar structures were concerned, the effective distribution coefficient (Ke), the ratio of the solute concentration in the solid to that in the bulk liquid, decreased gradually with the increase in U. The decrease of Ke with U was larger in Al-Cu alloys than in Al-Mg alloys. The effect of U became larger as the solidification rate and the temperature gradient of specimen decreased. On the other hand, Ke of the specimens with the equiaxed structures should be nearly equal to unity independent of U.View full abstractDownload PDF (594K) -
Hakaru Masumoto, Kiyoshi Watanabe1978 Volume 42 Issue 3 Pages 256-260
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn equilibrium diagram of Co-2.92∼30.05 wt%Fe binary alloys has been investigated by means of X-ray diffraction, thermal expansion measurement and microscope observation. The result shows that the fcc→d·hcp transformation in Co-rich alloys of the Co-Fe system takes place very slowly and its completion takes considerable time in the case of cooling, and that the phase transformation temperature is nearly independent of heating and cooling rates.
The equilibrium diagram of the alloys at room temperature is quite similar to that obtained previously by Masumoto; a γ phase between about 4.7 and 20.5%Fe, an α+γ phase between 20.5 and 22%Fe, and α single phase when the Fe concentration exceeds 22%.View full abstractDownload PDF (583K) -
Ishi Miura, Hitoshi Hamanaka1978 Volume 42 Issue 3 Pages 260-266
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUnidirectional recrystallization in cold-swaged Ni was investigated over a temperature gradient range of 140∼900 K/cm. It was found that recrystallization structures depend strongly on the temperature gradient and transfer rate of the hot zone in addition to the cold-swaged reduction. Secondary recrystallized grains at high temperature gradients grew larger and loger with increased swaging reduction. Single crystals were found in the specimens cold-swaged by 81% under suitable conditions. These conditions were given by a curve drawn through the transfer rates of 0.55, 1.4 and 2.8 μm/s and the temperature gradients of 900, 660 and 450 K/cm respectively. Primary recrystallized region became narrower and the grain size just in front of the secondary recrystallization became smaller with increasing temperature gradient. At the temperature gradient of 900 K/cm the recrystallized structure consists of highly elongated grains aligned parallel to the transfer direction, that grew directly from the deformed region. The growth process was observed up to the rate of 27.8 μm/s.View full abstractDownload PDF (729K) -
Hirofumi Miyaji, Satoshi Watanabe, Ryôichi Kaneko1978 Volume 42 Issue 3 Pages 266-274
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is the purpose of this study to investigate the possibility of controlling the texture of 17 Cr stainless steel sheet to the {100}⟨011⟩ type which is proposed to be appropriate for a can used for a canned motor. The characteristics of the textures were studied on the hot-rolled sheet, which did not recrystallize during the hot-rolling process, and on the same sheet after annealing. The variation of texture in the cold-rolling and annealing processes was studied, paying particular attention to the differences in the initial orientation.
The results are as follows:
(1) The texture of the as-hot-rolled sheet consists of a strongly developed {100}⟨uvw⟩ orientation, whereas that of the annealed sheet is nearly random due to recrystallization.
(2) The {100}⟨uvw⟩ texture component rapidly decreases with cold-rolling and reduction. The cold-rolling recrystallization textures of 70% cold-rolled sheets mainly consist of the {100}⟨011⟩ component.
(3) A canned motor with a sheet having the {100}⟨011⟩ texture shows high efficiency.View full abstractDownload PDF (1346K) -
Susumu Ikeno, Shigeoki Saji, Shigenori Hori1978 Volume 42 Issue 3 Pages 275-280
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe strengthening by thermo-mecanical treatment in both Cu-4%Ti and Cu-4%Ti-0.11%Zr alloys was studied by micro-hardness measurements, tensile tests, electron microscopy, and X-ray diffraction.
The following conclusions were obtained.
When the both alloys preaged at 450°C for various times were cold-rolled up to 90% and then annealed finally at 450°C for a short time, their strength was remarkably increased up to 1300 MPa in ultimate tensile strength.
As the annealing temperature was lowered the annealing time required to obtain a maximum hardness by the final annealing was longer.
The increment of hardness by the final annealing depended on the amount of cold rolling, and linear relationships existed between the increments in hardness by cold working and final annealing.
When preageing time was increased, the increment in hardness by the final annealing was decreased to a minimum and then it was increased. The maximum value of the increment in hardness was obtained for the specimens with few supersaturated Ti atoms after preageing.View full abstractDownload PDF (484K) -
Hakaru Masumoto, Yuetsu Murakami, Naoji Nakamura1978 Volume 42 Issue 3 Pages 280-284
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMagnetic properties, electrical resistivity, hardness and microstructure have been studied for the Fe-Ta alloys containing less than 7%Ta. The alloys are water-quenched from various temperatures over the α-γ transformation point, cold-drawn by more than 50% reduction in area and then reheated at 400∼1000°C for less than 5 h.
The magnetic properties of those alloys depend remarkably on the reduction rate, reheating temperature and reheating time after solution treatment. An Fe-2.9%Ta alloy reheated at 700°C for 30 min after water-quenching from 1050°C and cold-drawing of 97.2% reduction exhibits the following excellent properties: magnetic induction at 8 kA/m B8=1,78 T, residual induction Br=1.59 T, coercive force Hc=0.95 kA/m, squareness ratio Br⁄B8=0.89 and squareness \sqrt(BH)max⁄BrHc=0.92. The electrical resistivity and Vickers hardness of this alloy are 0.127 μΩ·m and 209, respectively.View full abstractDownload PDF (572K) -
Yasunari Kaneko, Yukio Suginohara1978 Volume 42 Issue 3 Pages 285-289
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn attempt has been made to find out a method to determine the quantity of three kinds of oxygen ions, i.e. O0, O− and O2−, exsisting in the vitreous silicate.
In the previous paper, three kinds of oxygen ions were analyzed from the spectra of O 1s binding energy by the aid of an electronic computer. In this paper, the analysis was made in terms of the chemical shift of Si 2p binding energy.
The main results obtained were as follows:
(1) The Si 2p binding energy for SiO2 was 103.5 eV, it decreased with increase in modifier oxide content and indicated a minimum value when all silicate anions were completely dissociated to the isolated SiO44− ions.
(2) The Si 2p binding energy for 2MeO·SiO2 generally decreased with decreasing electronegativity of the metallic ion.
(3) The value of Si 2p binding energy was proportional to the number of O− ions which combined with a Si atom in the silicate anion.
(4) The results of quantitative analysis of three kinds of oxygen ions by the use of the chemical shift of Si 2p energy also agreed very well with the previous results determined from the spectra of O 1s binding energy.View full abstractDownload PDF (426K) -
Kazuhiko Takeshita, Masayoshi Hasegawa1978 Volume 42 Issue 3 Pages 289-294
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs a new technique, the Spray-Dispersion Method, which can produce a steel containing homogeneously dispersed fine oxide particles sprayed from outside into the molten steel stream, has been developed by the authors. Al2O3-or ZrO2-dispersed 18 chromium-8 nickel stainless steels containing 1 at% niobium were produced by this method, and the distribution of oxide particles and the mechanical properties of the stainless steels were studied.
The homogeneous distribution of fine oxide particles was obtained for 18 chromium-8 nickel stainless steel. Because of fine dispersed particles, the strength of steels increased with their volume fraction; for example, 2.12 vol%ZrO2 caused an increment of 74 MPa in proof strength and 78 MPa in tensile strength, and those increments were maintained even at 973 K. Furthermore fine oxide particles contributed to the increase of creep rupture strength, and this tendency became more pronounced at the longer rupture time side. As a result, the production of oxide dispersion strengthened stainless steel has been established by the Spray-Dispersion Method.View full abstractDownload PDF (620K) -
Akihisa Inoue, Tsuyoshi Masumoto, Michio Kikuchi, Tetsuroh Minemura1978 Volume 42 Issue 3 Pages 294-303
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCompositional effect on the structural changes during heating up to 700°C has been examined with a number of amorphous alloys of X-Si-B and (X, Y)78Si10B12 (X, Y: Fe, Ni, Co) by differential scanning calorie and Vickers hardness measurements, transmission electron microscopy and X-ray diffraction analysis.
(1) The amorphous phase of X-Si-B alloys is obtained in the compositional range of 20 to 30 at% metalloid contents. The crystallization temperature of these amorphous alloys is low at low metalloid contents, but it increases with increasing metalloid content. The crystallization process changes in the vicinity of 27∼29 at% metalloid contents. Below and above this metalloid content, the amorphous alloys crystallize following the process of Am→Am+MS-I→MS-I+MS-II→Stable. In the lower metalloid contents the MS-I phase is a crystal with the same structure as each mother metal, while in the higher contents it is a compound containing a large amount of metalloid elements. At the intermediate metalloid content (27∼29 at%), these MS-I phases do not precipitate, but MS-II phase appears directly from the amorphous matrix and transforms finally to stable phases.
(2) The crystallization process of amorphous (X, Y)78Si10B12 alloys proceeds through two metastable phases (MS-I and MS-II) and finally to stable phases. The crystalline structure of MS-I phase agrees well with that of equilibrium phase at room temperature for the X-Y binary alloys.View full abstractDownload PDF (977K) -
Akihisa Inoue, Tsuyoshi Masumoto, Hisamichi Kimura1978 Volume 42 Issue 3 Pages 303-309
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe change in fracture strain of several metal-metalloid amorphous alloys (Pd-Si, Fe-P-C, Fe-Si-B, Ni-Si-B, Co-Si-B) by a bending test has been examined as functions of the aging time and temperature below 500°C and the relationship between embrittlement and the crystallization process has been discussed.
(1) The tendency for the fracture strain to decrease by the isothermal aging differs depending on the composition of amorphous alloys; above all the embrittlement of the Fe-based alloys is remarkable as compared with those of other alloys.
(2) The critical temperature (Tf) at which fracture occurs is represented by a linear function of the logarithm of aging time (t); Tf=T0+a·logt. The degree of embrittlement can be evaluated by two parameters, namely, the constant, T0, and the embrittlement coefficient, a, which is the gradient of the linear function.
(3) The embrittlement coefficients for Pd-, Ni- and Co-based alloys are small and these alloys become brittle by precipitation of the MS-I or MS-II phases. On the other hand, Fe-based alloys have a large embrittlement coefficient and become brittle at the incipient stage of crystallization. The reason why only Fe-based alloys become brittle prior to the appearance of the MS-I or MS-II phases may be due to the internal strain generated by the nucleation of a fine body-centered cubic crystal in amorphous structure.View full abstractDownload PDF (550K) -
Hisashi Kawabe, Kaizo Kuwahara1978 Volume 42 Issue 3 Pages 310-316
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe dynamic characteristics of the 3-lumped parameters vibration model are analyzed by making them correspond to the anelastic behaviors of materials, and the following results are obtained:
Both characteristics in the transient and resonant response of the model can describe the mechanical relaxation (internal friction and modulus defect) of the real solid more concretely and accurately. Regarding the waveforms of the transient response, the phenomena that the asymmetrical damped oscillations are sometimes observed in the high damping relaxation system, such as Al-Zn eutectoid alloys and Bi films, can be explained from the relative geometrical configurations of the characteristic roots on the s (Laplace operator)-plane; for large ΔK (ralaxation strength) of about 0.5, the asymmetry is pronounced, while for small ΔK(\simeq10−3), it is scarecely appreciable. Even when the asymmetry is pronounced, the method for the evaluation of damping capacity is the same as the usual one based on the relative decrement in vibrational amplitude. On the other hand, as for the resonant response, the resonant amplitude and frequency vary with the viscous coefficient ratio which is a function of temperature. Especially at the resonant curve, whose peak becomes the lowest, the half-width is equal to a half of ΔK. Furthermore, from the measurement of the resonant frequency or the resonant amplitude at the resonance peak and from their normalized values, the value of ΔK can be estimated with relative ease.View full abstractDownload PDF (520K) -
Taishi Moroishi, Yoshiaki Shida1978 Volume 42 Issue 3 Pages 316-323
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe oxidation of pure titanium was studied in superheated steam at 400∼550°C. The effects of prior cold working and several heat treatment conditions on the oxidation were examined and also the effects of the addition of small amounts of iron and oxygen were investigated. The oxidation mechanism of pure titanium is discussed in relation to the scale structure and the oxidation kinetics. Hydrogen absorption rate was also measured. As a result, the following conclusions were drawn:
(1) The oxidation of pure titanium in steam was faster than in air and breakaway oxidation was observed above 500°C after the specimen had gained a certain weight. Prior cold working and heat treatment conditions scarcely affected the oxidation rate, whereas the specimen containing small amounts of iron and oxygen showed a little more rapid oxidation.
(2) At 500 and 550°C a dark grey inner scale and a yellow-brown outer scale were formed. The outer scae was apt to exfoliate after the occurrence of breakaway oxidation. At 400 and 450°C only a dark grey scale was observed. All of these oxides were identified as the rutile type, TiO2. Furthermore, the presence of a thin and uniform oxygen rich layer beneath the external scale was confirmed at all test temperatures.
(3) The measured weight gain approximately followed the cubic rate law; this would be expected for the following reason; one component of the weight gain is due to the dissolved oxygen, the amount of which remains constant after the early stages of oxidation. The second component is due to the parabolic growth of the external TiO2 scale. When these contributions are added a pseudo-cubic weight gain curve results.
(4) It was shown that 50 percent of the hydrogen generated during the oxidation was absorbed into the metal.View full abstractDownload PDF (851K)
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