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Volume 39, Issue 2
Displaying 1-18 of 18 articles from this issue
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Yoshinobu Tahara, Kazutoshi Shinohara, Hironori Kuroki, Tetsuo Eguchi1975 Volume 39 Issue 2 Pages 105-110
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn FeCo alloy, the variation of lattice constant in isothermal annealing was observed by means of X-ray diffraction, and the experimental results were analyzed by the use of an approximate rate equation. This rate equation has been derived from the two conditions, namely, the symmetry between two sublattices in the B2 type structure, and the stability of the equilibrium state. The equation has an advantage over the others in that it is simpler and more general, but the physical meaning of the parameters used in this analysis is not clear. For this reason, the rate equation was compared with the one derived by Takagi and Oguchi the analogy to the chemical rate theory, and the activation energy for ordering in FeCo alloy was estimated to be 52.0 kcal/mol.View full abstractDownload PDF (490K) -
Katashi Masumoto, Isao Nakatani1975 Volume 39 Issue 2 Pages 110-117
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCuCr2Se4 single crystals were grown by a chemical transport method. The single crystals obtained were crystallographically characterized by optical microscopy, Laue method and X-ray topographic techniques. The magnetic properties of these crystals have been measured. These results are summarized as follows.
(1) CuCr2Se4 single crystals, which were octahedral up to an edge length of about 3 mm, were grown by a chemical transport method from the CuCr2Se4 polycrystalline powder using iodine carrier under the condition of the feed end, 950°C, and that of the growth end, 800°C.
(2) The optimum temperature conditions of the chemical transport reactions using iodine carrier for the crystal perfection were determined to be 850∼900°C for the feed end, 800°C for the growth end.
(3) The magnetic properties have been measured, using the single crystals obtained. The saturation magnetization was determined to be 270 emu/cc, and the magnetic anisotropy constant K1 was found to be −0.9×105 erg/cc at room temperature. The high-temperature susceptibility obeys the Curie-Weiss law. The paramagnetic Curie temperature θ and the Curie constant were determined to be 441°K and 2.55 emu·deg/mol, respectively. The ferromagnetic Curie temperature Tc was determined to be 430°K.View full abstractDownload PDF (1069K) -
Toshiyuki Suzuki, Katashi Masumoto1975 Volume 39 Issue 2 Pages 117-121
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanical properties of intermetallic compound CoZr having a CsCl structure have been measured. Prior to measurements, the composition at which the CoZr phase exists and the condition of heat-treatment to obtain homogeneous CoZr were determined.
The phase exists stably at the stoichiometric composition and has a restricted homogeneity range even at high temperatures. No evidence to occur peritectic decomposition on heating at intermediate temperatures was obtained. The CoZr is, therefore, considered to melt congruently. In the temperature range from room temperature to 900°C, neither order-disorder transformation nor martensitic transformation takes place.
Though it is difficult to obtain completely homogeneous CoZr because of the restricted homogeneity range, CoZr containing a small amount of the second phase is ductile at room temperature and showed tensile elongation up to 7%. Ultimate tensile strength of about 37 kg/mm2 was given in the same specimen. The hardness-temperature relation of the sort H=Aexp−BT holds for CoZr. Utilizing the equation, the softening coefficient of 4.95×10−3 °K−1 above the critical temperature was obtained.View full abstractDownload PDF (656K) -
Ichiro Shiota, Osamu Watanabe1975 Volume 39 Issue 2 Pages 122-126
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMicrostructures of a nickel coated carbon fiber at high temperatures were studied by X-ray diffraction and an electron probe microanalyser, and they were compared with the results of observations by a scanning electron microscope.
By holding carbon fiber coated with nickel at a high temperature over 700°C, a white ring moving to the center of fiber was observed in the cross section of the carbon fiber.
The white ring was confirmed to be nickel metal, not nickel carbides, by X-ray diffraction and electron probe microanalysis. The area of the carbon fiber passed by the nickel ring showed a flaky appearance, and the carbon was graphitized at the area. The flaky area was oriented less preferably than that in the intact area.
It seems reasonable to consider the moving of the nickel ring accompanied by graphitization of the carbon fiber in such a way that the carbon atoms dissolve into nickel metal from the less graphitized part, diffuse in it, and deposit as graphite on a comparatively well graphitized part of the carbon fiber. As the deposited graphite is stable than carbon in the intact area, the nickel ring dissolves carbon atoms inside of the ring and discharge them as graphite outside of it, thus the nickel ring moves to the center of the carbon fiber and finally aggregates there as a white speck.View full abstractDownload PDF (437K) -
Hakaru Masumoto, Michio Kikuchi, Showhachi Sawaya1975 Volume 39 Issue 2 Pages 127-130
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSYoung’s modulus at low and high temperatures, thermal expansion and hardness at room temperature have been measured with Mn-Cu-V alloys subjected to various heat treatments and cold working. The ternary alloys annealed at 900°C showed distinct anomalous changes related to antiferromagnetic\ ightleftarrowsparamagnetic transformations in Young’s modulus vs temperature curves. The temperature coefficient of Young’s modulus is altered appreciably by annealing, water quenching, cold working, and reheating after cold working or water quenching. It also shows a large composition dependence. The presence of a large positive maximum in the temperature coefficient of Young’s modulus vs composition curve demonstrates the Elinvar property of the alloys.View full abstractDownload PDF (329K) -
Hakaru Masumoto, Showhachi Sawaya, Michio Kikuchi1975 Volume 39 Issue 2 Pages 130-133
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSYoung’s modulus at low and high temperatures and thermal expansion at room temperature have been measured so as to investigate the effects of additions of aluminum and tantalum on the Elinvar property of nickel at high temperature. In the alloy systems Ni-Al and Ni-Ta, the critical temperature at which the Elinvar property of nickel appears falls down gradually along the magnetic transformation point with increasing addition of each element. Also, a small minimum linear coefficient of thermal expansion appears near the composition at which the Elinvar property is revealed at room temperature.View full abstractDownload PDF (286K) -
Tsuyoshi Masumoto, Hiroshi Kimura1975 Volume 39 Issue 2 Pages 133-141
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe elastic, plastic and fracture behaviors under tension and the changes in these properties during and after heating at various temperatures have been studied for amorphous Fe80-P15-C5 alloy. The amorphous specimens were prepared to have a shape of filament about 30μ thick and 0.5 mm wide using a centrifugal quenching apparatus developed in our laboratory. The mechanical tests were performed over a temperature range between −195 and 500°C through a range of strain rates from 6.7×10−5 to 6.7×10−2 per sec. The amorphous alloy exhibits extremely high strengths such as about 230 kg/mm2 in proportional limit and about 310 kg/mm2 in fracture strength. Young’s modulus is about 12.4×103 kg/mm2. Its tensile elongation is only 0.03% at room temperature. The fracture strength decreases as the strain rate increases. The tensile strength and Young’s modulus depend significantly upon temperature and the fracture elongation increases rapidly above about 300°C. The fracture by localized shear deformation occurs over a wide temperature range of −195 to about 300°C and the fracture surface consists of a smooth region produced by shearing and a vein-like region produced by plastic instability. Transformation from the amorphous phase to the crystalline phase results in lower fracture strength, higher hardness and more brittle manner.View full abstractDownload PDF (1022K) -
Hisaoki Sasano, Hirozo Kimura1975 Volume 39 Issue 2 Pages 142-147
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSerrated yielding was clearly observed between 330 and 460°C at a strain rate of 2.22×10−4 sec−1 in Ti-2 at%Zr alloy, while in a commercially pure titanium it was not so clear. Two types of serrations were observed in the alloy. One type is the serrations with a regular periodicity and the other is the serrations with relatively large stress drops which occur intermittently. In cases where the strain increases, the strain rate decreases or the grain size decreases, the stress amplitude of the regular serrations increases. Examination of the temperature and strain rate dependence of the regular serrations suggests that serrated yielding in Ti-2 at%Zr alloy is probably dominated by the diffusion of both zirconium and interstitial impurity atoms. The regular serrations, therefore, must be closely related to the strong interaction between a dislocation and an interstitial impurity atom which is at the octahedral site distorted locally by a zirconium atom.View full abstractDownload PDF (485K) -
Tetsuyuki Ikeda, Seiki Nishi1975 Volume 39 Issue 2 Pages 147-155
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBy rapid quenching of Al-1∼5%Mn alloys from the liquid state, an equilibrium structure, a structure formed by movement of the eutectic point, an incompletely super-saturated solid solution and a completely solid solution were obtained successively with increase in solidification rate. Micro-Vickers hardness measurement, tensile test and thermal analysis were used to examine the relations between the mechanical properties and these structures. The result obtained were as follows:
(1) With increase in solidification rate (V) (or change of solidified structures), Micro-Vickers hardness (Hv), ultimate tensile strength (σB) and elongation (δ) rose according to the relation of Y=AV+B or Y=C (Y: σB, Hv, δ, V: solidification rate, A, B, C: constant).
(2) The ranges of solidification rate at which each structure was formed, were shown by a diagram for Al-1∼5%Mn alloys.
(3) The constitution diagrams to show the relations of average solidification rate—thickness distance and Mn content—thickness distance were obtained.View full abstractDownload PDF (1607K) -
Tadashi Chihaya, Ryoichi Urao, Shinichiro Yoshioka1975 Volume 39 Issue 2 Pages 156-161
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMetals are nitrided by nitrogenion-bombarding on their surfaces. In order to apply this method as a method of surface hardening, it would be desirable to permeate a large number of nitrogen atoms into metals for a short time, i.e. to bombard them with a high ion current density at high temperature. From this point of view, the ion-nitriding method in glow discharge is being empoyed industrially, but many experimental basic data are not available. We tried to ion-bombard some steels in N2-H2 mixing gases under some different bombarding conditions, and examined their hardness, nitride products formed in the surfaces layer, etc. Results obtained are as follows.
(1) The iron and steel surfaces are hardened by nitrogen-ion-bombarding. The hardnesses of the steels containing Cr, Mo and Al are much higher than that of iron and plain low carbon steel.
(2) The highest hardness is obtained by nitriding iron and S 15 C steel in the gas of 70 vol%N2 and SCM 21, SACM 1 and SUS 304 steels in the gase of 30 to 50 vol%N2, respectively. The maximum hardness and the hardness change, in accordance with the relation between hardness and gas concentration, decrease with the increase in gas pressure.
(3) The highest hardness is obtained by nitriding iron and S 15 C steel at from 550 to 600°C and SCM 21, SACM 1 and SUS 304 steels at 500 to 550°C, respectively.
(4) ε-Fe2–3N, γ′-Fe4N, γ-Fe and α-Fe phases are detected from nitrided surfaces by X-ray diffraction. The ε-Fe2–3N phase is formed in the gas of high N2 concentration and is hardly formed in the gas lower than 30 vol%N2.View full abstractDownload PDF (505K) -
Makoto Kikuchi, Tohru Tanaka, Ryohei Tanaka1975 Volume 39 Issue 2 Pages 162-168
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMorphology of Mo2C precipitated in a Ni-9.0 at%Mo-0.83 at%C alloy aged at 900°C has been studied by means of transmission electron microscopy. The shape of intragranularly precipitated Mo2C is a thin hexagonal plate having two broad faces of {00·1}Mo2C and six side planes of {10·0}Mo2C type. The plate forms on {111}Ni matrix planes. Its orientation relationship with the matrix is (00·1)Mo2C\varparallel(111)Ni, [11·0]Mo2C\varparallel[1\bar10]Ni.
The growth direction as well as the orientation relationship of Mo2C fibres observed in isothermally transformed Fe-Mo-C alloys by other investigators has been discussed on the basis of the present observations.
The stacking fault energy of Mo2C is estimated to be relatively small. This accounts for the frequently observed stacking fault in the Mo2C plate precipitated in the present alloy.View full abstractDownload PDF (1026K) -
Hiroyasu Mitani, Kazuhiko Majima, Yuko Hanatate1975 Volume 39 Issue 2 Pages 168-174
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe sintering characteristics of the Fe-C binary mixed powder compacts containing up to 3.0 wt%C were investigated by the dilatometric method. Three kinds of Fe-1.0 wt%C binary mixed powder compacts; each containing electrolytic, atomized and reduced iron powder with different H2 loss, were used in order to examine the process of the carbon diffusion into iron and the decarburization, by means of the dilatometric method, measurement of the degree of vacuum and the carbon analysis.
The results obtained are summarized as follows:
(1) After the α→γ transformation during heating in vacuum of 10−5 mmHg for the Fe-C binary mixed powder compacts, the expansion was observed, the amount of which was nearly in proportion to the amount of additional graphite, and the expansion curve in dilatation and the combined carbon concentration curve well agreed. This means that the carburization was done mainly by the carbon diffusion through the contacting surface of graphite and iron powder rather than through the medium CH4 or CO gas.
(2) From the vacuum measurement, it was apparent that the amount of gas discharge from the specimen with the reduced iron powder was by far larger than that from the other specimens. On the contrary, its dilatational expansion was minimum, indicating that the specimen was not swelled by the gas pressure.
(3) Carbon diffusion into α-Fe was scarcely observed in H2 gas sintering, while in vacuum sintering carbon diffusion into α-Fe was about 0.1 wt%. However, the carbon diffused into γ-Fe more rapidly in H2 sintering than in vacuum. Consequently the dilatational expansion in the former was larger than in the latter. A similar relationship between the dilatational expansion curve and the curve of carbon concentration in vacuum sintering was also applicable to the case of sintering in H2 gas.View full abstractDownload PDF (720K) -
Toshio Honma, Hiromi Takei1975 Volume 39 Issue 2 Pages 175-182
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to clarify the effect of heat treatment on the martensitic transformation in the TiNi compound, the electrical resistivity vs temperature curves of TiNi containing hyper-stoichiometric concentration of nickel which were heat-treated under various conditions were obtained. TiNi containing more than 51 at%Ni showed a remarkable quenching effect. The Ms temperature of water-quenched specimens decreased with increasing nickel concentration. The Ms temperature of Ti-50 at%Ni was constant regardless of the change in quenching temperature, whereas that of Ti-51 and 52 at%Ni decreased with increasing quenching temperature above 500°C. The Ms temperature of Ti-51 at%Ni, however, became constant by quenching from a temperature above 600°C. In Ti-52 at%Ni the Ms temperature decreased below liquid nitrogen temperature by quenching from a temperature above 750°C. The Ms temperature increased up to −5°C by aging at 500°C after water quenching from 1000°C in both Ti-51 and −52 at%Ni. In Ti-49.5, 50.0 and 50.4 at%Ni the appearance of a peak in resistivity-temperature curve was observed after some complete thermal cycles. The Ms temperature decreased during initial five cycles and then became constant. From the results obtained by electrical resistivity measurement and X-ray diffraction, it is concluded that the TiNi compound has a CsCl-type ordered structure and order-disorder transformation or peritectoid transformation does not exist in the temperature range from the Ms temperature to 1000°C. It is also found that the nonstoichiometric range of the compound becomes narrower with decreasing temperature and the maximum nickel concentration at 500°C is 50.8 at%Ni.View full abstractDownload PDF (623K) -
Eiji Fukushima, Akira Goto1975 Volume 39 Issue 2 Pages 182-187
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSObservations on the changes in microstructures and electrical resistivities with the serrations, and other morphological observations on the serrations were made to make clear the type, the mechanism and the characteristics of the serrations that were observed in various metals and alloys at cryogenic temperatures. Conclusions obtained are as follows:
(1) Serrations observed at cryogenic temperatures are classified morphologically into three types: (a) one accompanying martensitic transformation, (b) one accompanying deformation twinning, and (c) one accompanying coarse slip.
(2) Serrations with martensitic transformation are observed, for instance, in 18-8 stainless steel. In this case, martensitic transformation plays an important role in load drops at the serrations.
(3) Serrations with deformation twinning are observed, for instance, in copper and titanium. In these cases, about 1×105∼8×106 of twins are formed locally with a serration.
(4) Serrations with coarse slips are observed for instance, in aluminum and duralumin. In these cases, serrations occur as a result of slip in the regions of comparatively small strain-hardening rate. They are regarded as the repetition of Johnston-type yielding.
(5) Serrations observed in aluminum and duralumin are considered to be caused instantaneously by large deformations occurring near the places where dislocations are by chance released from short-range obstacles, on which dislocations are apt to be locked at cryogenic temperatures because of the going down of thermal fluctuation.View full abstractDownload PDF (709K) -
Iwao Katayama, Nobumasa Kemori, Zensaku Kozuka1975 Volume 39 Issue 2 Pages 188-194
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSE.M.F. of a galvanic cell with the solid electrolyte (ZrO2+CaO) was measured to determine the activities of gallium in the temperature range of 800∼1000°C and composition range of 0∼58.9 at%Ga for solid Co-Ga alloys, and thermodynamic functions were derived from the results. The cells used were as follows:
Pt, Re, Ga, Ga2O3/ZrO2(+CaO)/Fe, FexO, Pt
Pt, Re, Co-Ga alloy, Ga2O3/ZrO2(+CaO)/Fe, FexO, Pt.
Activities of gallium showed large negative deviations from Raoult’s law in the whole composition range investigated. Activity changes with composition in cobalt rich α-solid solution were small, but very large in the β(CoGa)-phase. Activities of cobalt showed very small positive deviations from Raoult’s law in the α-solid solution, but very large negative ones in the β-phase. Activities of gallium and free energies of formation showed larger values than those of Ni-Ga alloys. Larger solubilities of gallium in cobalt in the temperature range of 800∼1000°C than those shown in the phase diagram of Elliott were found. Standard free energy of formation of Ga2O3(s) was shown by
(This article is not displayable. Please see full text pdf.)
\ oindentin the temperature range of 720∼1030°C.View full abstractDownload PDF (564K) -
Hirofumi Miyaji, Satoshi Watanabe1975 Volume 39 Issue 2 Pages 194-198
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to clarify an influence of the distribution of the martensite phase in a hot-rolled sheet on the ridging phenomenon 17Cr stainless steel, the effect of the homogenizing treatment at a temperature immediately above or under the region, in which both austenite and ferrite coexist, on the ridging phenomenon was investigated. The results are as follows.
(1) The uniform distribution of the martensite phase in a ferrite matrix was obtained by homogenizing and subsequent quenching.
(2) The favourable effect of the homogenizing treatment was confirmed from the fact that the ridging was prevented perfectly by this treatment. This treatment can randomize the texture almost completly also in the local region within a sheet.
(3) The occurrence of ridging can not be simply estimated from the texture determined by the usual pole figure method.
(4) Ridging phenomenon depends on the distribution feature of some texture components in a local region within a sheet and at the same time on thier size and shape.View full abstractDownload PDF (965K) -
Takeo Yokobori, Hashime Shimura1975 Volume 39 Issue 2 Pages 199-205
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh temperature creep behavior of Nimonic 75 alloy was studied under the test condition of the cavitation fracture. At what stage of the creep curve the cavity would nucleate and how it grows was observed continuously on the specimen surface by using a high-temperature microscope. In order to examine the shape of the cavitation fracture surface, electron fractomicrographical observations were made. Mesurement of angular distributions for grain boundary cavities was also carried out.
From the studies the following conclusions are obtained:
(1) The cavities on the surface and the interior of the specimen are initiated during the stage of transient creep and will grow during the stage of steady creep.
(2) The grain boundary sliding appears to contribute to the initiation and the growth of the crack of cavity type.
(3) The most probable value of the direction of the grain boundary at which cavities initiate is in agreement with the direction of the maximum shear stress component of applied stress.View full abstractDownload PDF (1845K) -
Junji Shibata, Sanji Nishimura1975 Volume 39 Issue 2 Pages 206-212
Published: 1975
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe distribution of Cu, Ni and Co between an aqueous solution of constant ionic strength and Versatic Acid 911 diluted with benzene was studied. Only one extracted species of Cu was revealed to have a dimeric structure of the composition (CuR2·RH)2, while both monomer and dimer were found in the extraction of Ni and Co. The compositions of the extracted species were NiR2·4RH and (NiR2·2RH)2, and CoR2·4RH and (CoR2·2RH)2, respectively.
The effect of sulphate and chloride ions on the extraction of these metals was also investigated. These ions are not extracted into the organic phase, and they affect the metal extraction only by forming metal complexes with sulphate and chloride ions in the aqueous solution. However, the effect of sulphate and bisulphate ions appears when a stronger extractant than Versatic Acid 911 such as D2EHPA is employed.View full abstractDownload PDF (508K)
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