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Volume 25, Issue 1
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Masataka Sugiyama, Hisashi Suzuki1961 Volume 25 Issue 1 Pages 1-4
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of heat treatment upon some room-temperature properties of TiC-31 wt% cermet were mainly studied. The hardness, transverse-rupture strength, X-ray parameter, curie temperature and microstructure of the alloy held in vacuum at 700∼1300°C for 0.5∼25 hrs, or quenched from 700∼1300°C were observed. As the results, it was especially noticed that the TiC grains in this TiC-Ni system after a long time of heating have coalesced to form clusters, and such a change of microstructure would be detrimental to the mechanical properties at low-temperature.View full abstractDownload PDF (540K) -
Masataka Sugiyama, Hisashi Suzuki1961 Volume 25 Issue 1 Pages 4-8
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor obtaining basic informations on the vacuum-sintering of TiC base cermets containing Ni, Cr and Co as the binder metal, the cermet containing 40 wt%Ni-Cr-Co (3/1/1) was mainly studied. And some room-temperature properties such as the transverse-rupture strength, the hardness, the density, the curie temperature and the microstructure of the cermet were checked as a function of wet ball-milling times up to 200 hrs, sintering temperatures ranging from 1270° to 1440°C in usual sintering time of 1 hr and Mo additions-up to 5 wt% as a substitute for Co in the binder.View full abstractDownload PDF (637K) -
Masataka Sugiyama, Hisashi Suzuki1961 Volume 25 Issue 1 Pages 8-11
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of heat treatment on some room-temperature properties of 1280°×1 hr vacuum sintered TiC-50Ni-Cr-Co (Ni/Cr/Co=3/1/1) cermet were studied. The variation of transverse-rupture strength, hardness, X-ray parameter, curie temperature and microstructure of the alloy by heating in vacuum at 950∼1260°C for 5∼25 hrs or by quenching from 950∼1280°C was also observed. The main results obtained were as followed: (1) The change of the properties was closely related to the precipitation of chrome carbides in the cermet but except this, the nature of the variation was almost similar to thar in TiC-Ni cermet previously reported. (2) A more pertinent binder composition of the cermet was thought desirable, since its strength decreased after prolonged heating.View full abstractDownload PDF (501K) -
Yûnoshin Imai, Toshio Saitô1961 Volume 25 Issue 1 Pages 11-15
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanical properties and hardenability of multiple low-alloy high-strength steels, such as containing 0.3%C, 1.00%Cr, 0.3%Cu, 0.01%Ti, 0.002%B and 0∼0.5%Mo were studied. These steels have considerable excellent mechanical properties and hardenabilitys, even with no added Mo. By addition of Mo, the strength, the toughness and the hardenability of these steels were improved, and it was found that addition of 0.4∼0.5%Mo in these steels was most effective. The low-temperature transition properties in these steels, oil quenched and tempered to obtain Rc 32 hardness, were remarkably improved by addition of Mo. 0.42%Mo-added steels maintained about 5 kg-m V-nooch Charpy impact energy at −78°C a very high value for high strength steel which has the tensile strength over 100 kg/mm2.View full abstractDownload PDF (500K) -
Osamu Izumi, Hiroshi Fukuda1961 Volume 25 Issue 1 Pages 15-19
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of the temperature of solution-treatment (700∼850°) as well as cold-rolling prior to aging treatment (30 and 80% in reduction percentage) on the aging characteristics of Be-Cu alloys, containing a small amount of Ni between 150° and 550°C were investigated by measuring the hardness and observing the microstructure. A lowering of the temperature of solution-treatment remarkably reduced he velocity and the degree of age-hardening, but the change in aging curves at the respective temperatures was found not to be in proportion to the change of quenching temperature. Cold-working generally reduced the degree of age-hardening, and especially such discontinuous changes as abnormal softening or two-steps hardening have been observed at about 250∼350°C. The rate of hardening was greater in as cold-worked specimens than as-quenched ones, in the range of low-temperature aging, but it became obscure at higher aging temperatures owing to the abnormal change mentioned above. The results were discussed in relation to the microstructures observed.View full abstractDownload PDF (426K) -
Taira Okamoto, Masao Ibaraki1961 Volume 25 Issue 1 Pages 19-23
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe determination of oxygen in white iron was performed using a modified apparatus used in chlorine method. This method gives results in good agreement with those of vacuum-fusion method. Ferro-silicon was added to the iron-carbon (3%) melt for the purpose of preparing iron containing 3% carbon and 1% silicon. The oxygen content as FeO was independent from the holding temperature when the holding time of the melt after addition of ferro-silicon was shorter than 15 min, and the content approached the value caluculated from thermodynamic data on the equilibrium of iron-carbon (3%)-silicon (1%)-oxygen melt. When the holding time was longer than 20 min, the FeO content increased to supersaturated values and the SiO2 content increased with prolongation of the time. This phenomenon was not observed when the melt was held at high temperatures.View full abstractDownload PDF (454K) -
To-oru Furukawa, Tomo-o Sato1961 Volume 25 Issue 1 Pages 23-26
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS17%Cr-7%Ni stainless steel containing 0.93%Al was used for the experiments of acid corrosion resistance after several heat treatments such as solution treatment at 1050°, cooling from 750∼800°C in water or air and aging at 400∼500°C for 0.5∼500 hr. As corrosion reagents, 10 wt% sulphuric acid (30°C) and 40 wt% nitric acid (boiling) solutions were used. The following results were obtained; (1) Against 10 wt% sulphuric acid solution, this steel aged at a lower temperature than that for obtaining max. mechanical properties showed as strong corrosion resistivity as 18-8 stainless steel. Specimens heat-treated under such desirable condition attained a passive state in the soaking time up to 12 hr. (2) Against 40 wt% boiling nitric acid solution, this steel heat-treated under suitable conditions shows corrosion resistivity superior to that of 18-8 stainless steel.View full abstractDownload PDF (370K) -
Sanji Nishimura, Joichiro Moriyama, Isao Kushima1961 Volume 25 Issue 1 Pages 27-30
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe behavior of Ti in liquid-liquid solvent extraction of Ta and Nb using the organic solvent hexone was investigated in the four systems, namely, HF-hexone, HF-HCl-hexone, HF-H2SO4-hexone, and HF-HNO3-hexone. The results obtained can be summarized as follows: (1) By individually measuring the distribution coefficients of Ti, Ta, and Nb in the extracting systems, it was found that Ti can be separated sufficiently from Nb and Ta. (2) The extractability of Ti rose with a rise of mineral-acid concentration at constant HF acidity, and particularly sharply from 4.5 N HCl in HF-HCl-hexone system and from 10.6 N H2SO4 in HF-H2SO4-hexone system, but more gradually with rise of HNO3 concentration or HF concentration in HF-HNO3-hexone and HF-hexone systems. (3) In the limits of HF concentration investigated, the extractability of Ti lowered in the following order: In HF-HCl system>in HF-H2SO4 system>in HF-HNO3 system. (4) The cumulative Ti % in organic extract increased with repetition of extraction operation in HF-HCl, HF-H2SO4 and HF-HNO3. In HF-H2SO4 and HF-HNO3 the weight of Ti extracted in the second extraction, showed the maximum, whereas in HF-HCl system the fourth extraction produced the highest weight of extracted Ti. (5) In general, the extractability of Ti in HF-hexone system was smaller than in the other HF-mineral acid-hexone systems, but in HF-H2SO4 below 1.5NH2SO4, HF-HNO3 below 4.2NHNO3 and in HF-HCl below 0.8 N HCl, in which the HF acidity was 12.75 N, Ti was less extractable than in 12.75 NHF-hexone system, and the coextraction efficiency of Ta and Nb was also larger than in the latter.View full abstractDownload PDF (310K) -
Seita Sakui, Hideo Takei1961 Volume 25 Issue 1 Pages 30-33
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe changes of the rigidity modulus, the electrical resistivity, the hardness and the internal friction due to cold drawing and annealing were measured in 13Cr- and 18-8 stainless steel wires. The measurements were made on specimens of 0.7 or 0.6 mm diameter, using a torsion pendulum, a potentiometer and a micro-Vicker’s hardness tester. The results obtained were as follow: (1) The rigidity modulus of 13Cr stainless steel wire decreased slightly by the cold drawing above 30% in area reduction. (2) The internal friction of 13Cr stainless steel wire decreased remarkably by cold drawing of less than 10% reduction in area, but gradually increases by the drawing above 10% reduction. (3) The internal friction of 18-8 stainless steel wire increased remarkably with the amount of cold drawing less than 3% in reduction in area, but gradually increased by the drawing above 3% reduction. (4) The rigidity modulus of 13Cr- and 18-8 stainless steel wire increased slightly by annealing at a temperature higher than 150°. (5) The internal friction of 13Cr stainless steel wire decreased remarkably by annealing at 100∼300° after cold drawing, but increased at 400∼650°. (6) The internal friction of 18-8 stainless steel wires cold-drawn less than 22% in reduction in area decreased gradually by annealing at 100∼650°, but that of the wires cold drawn more than 49% in reduction decreased remarkably by annealing at 100∼250°, and increased by annealing at 550∼650°.View full abstractDownload PDF (367K) -
Seita Sakui, Hideo Takei1961 Volume 25 Issue 1 Pages 34-36
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe change of the rigidity modulus, the electrical resistivity, the hardness and the internal friction following age-hardening were studied with 17-7PH stainless-steel wire containing 1.24%Al.The measurement were made on specimen of 0.65 mm diameter, using a torsion pendulum, a potentiometer and a micro-Vicker’s hardness tester. The results obtained were as follows: (1) The hardness of 17-7PH stainless-steel wire increased remarkably by aging at 400∼500°, but only slightly by aging at 100∼200°. (2) The electrical resistivity decreased in three temperature ranges of aging, namely, 150∼200°, 300∼450° and 500∼600°. (3) The rigidity modulus increased in the aging temperature range of 100∼250° and 400∼500°, but decreased by aging above 550°. (4) The internal friction of 17-7PH steel wire decreased remarkably by aging at 100∼300°, but increased again by aging at 550∼650°.View full abstractDownload PDF (242K) -
Gunji Shinoda, Tadao Sano, Tadakazu Sakurai, Tadashi Kawasaki, Hisashi ...1961 Volume 25 Issue 1 Pages 36-40
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study was made to examine embrittlement of austenitic stainless steels of types 304, 316L and 347 caused by heating and by corrosion. The heating, in this case, does not mean only a simple heating of the specimen in a muffle furnace but also combination of fatigue or creep at elevated temperatures. An embrittlement of the specimen was examined by a tensile impact test using Charpy tester at room temperature. The impact value of the specimens slightly decrease due to the heating for long time, say about 100 hrs or more, and this may be attributed to carbide precipitation during the heating. After heating the specimens for up to 500 hrs, they were immersed into 0.1 mole uranium sulphate aqueous solution for up to 30 days. A drastic decrease in the impact value was observed and some of the specimens were degraded by the corrosion somewhat like a weathering of granite rocks. The phenomenon seems to be an extreme case of intergranular corrosion, and the composition of the specimen and the heating temperature prior to corrosion may be considered as major factors to control the phenomenon. Type 304 steel reveals such drastic corrosion embrittlement and the tendency is a most remarkable when the specimen is heated at about 600°C prior to the corrosion, while others reveal no appreciable corrosion embrittlement.View full abstractDownload PDF (474K) -
Tasaburo Nishioka, Yukio Yasukuni1961 Volume 25 Issue 1 Pages 40-43
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn diesem Bericht wurde der Einfluss der Wiederholten Biegungsbearbeitungen und der Dauerbiegungen auf die Härteverteilungen der verschiedenen Stahldrähte untersucht. Bei den Biegungsbearbeitungen: (1) Die Härte in Zugseite in letzter Biegung ist höher als die in Druckseite. (2) Mit zunehmender Biegezahl nimmt die Härte in wärmebehandelten Drähten erst rasch und sodann langsam zu, während in gezogenen Drähten die Härte zunächst zu-, insbesondere in Zugseite, und dann allmählich abnimmt. Bei den Dauerbiegungen: (1) Mit steigender Biegespannung wird die Härte in wärmebehandelten Drähten deutlich höher, insbesondere in Rand, und in gezogenen Drähten nur ein wenig höher. Auf jeden Fall wird bei der Spannung über die Elastizitätsgrenze die Härte erheblich höher. (2) Mit zunehmender Biegezahl wird die Härte in wärmebehandelten Drähte höher, insbesondere in Rand, und in gezogenen Drähte sind die Änderungen der Härte unbedeutend. (3) Die Zunahme der Härte ist beim Draht mit niedriger Wärmebehandeltfestigkeit grösser als beim Draht mit hoher Festigkeit.View full abstractDownload PDF (369K) -
Shigetoshi Takayanagi1961 Volume 25 Issue 1 Pages 44-48
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe X-ray line broadening from tungsten powder has been studied in relation to its oxidation rate. If βcosθ is plotted against sinθ, β being the line breadth at half maximum at Bragg angle θ, a crooked line is obtained that is inclined to the sinθ axis on an average. The results show that the oxidation rate is closely related to the average inclination of the crooked line and the level height of βcosθ corresponding to (200), as measured from that corresponding to (110). A change of such a relative level height and of the inclination on heating or pressing the powder is accompanied by decrease or increase of the oxidation rate. The shape of the crooked line and oxidation rate of tungsten powder are independent of the particle size and the quantity that has been dissolved. This indicates that the crystal structure is homogeneous throughout the whole part in any particle. It is believed that the phenomenon of such line broadening is dependent on the crystallite size, lattice distortion and irregularities which greatly affect the chemical reactivity.View full abstractDownload PDF (450K) -
Yû Yokoyama1961 Volume 25 Issue 1 Pages 48-52
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new type transient discharge source unit was constructed, by means of which a spectrochemical method was studied to determine acid-soluble aluminium in iron and steel with a porous-cup electrode. With this source unit various discharges are produced by varying the circuit constants (C, R, and L) and the spectra emitted at any given phase of discharge cycles can be photographed. In the present study a relation between these constants and an excitation index was clarified, and excitation conditions were investigated to obtain the stable discharge sufficiently sensitive to micro amount of aluminium. The material and the pre-burning procedure of porous-cup electrodes, which have an important effect upon the sensitivity and the reproducibility, were examined and finally the analytical method was established, by which 0.005 to 0.05 per cent acid-soluble aluminium in iron and steel was determined with the analytical line pair of K I 4044.14 A/Ål I 3961.53 Å.View full abstractDownload PDF (434K) -
Nakaaki Oda, Mitsuru Idohara1961 Volume 25 Issue 1 Pages 52-56
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study of quantitative spectrographic analysis of metallic impurities in high-purity tantalum metal and its compounds has become increasingly important because of the availability of such metal for the electrolytic condenser and the atomic engineering materials. In order to use a medium quartz spectrograph which is unsuitable for the analysis of such an element of complex spectrum as tantalum because of its poor resolving power, an attempt was successfully made to overcome its disadvantage by selecting the optimum condition and using an intermittent AC-arc source unit. The experiments were carried out to select the optimum conditions of excitation, the mixing ratio of carbon powder added as buffer, the formula of relative intensity and the analytical line pairs, and to find the sources of serious errors. This method in which a sample is converted to oxide, can be applied to metallic tantalum of powder or ingot form and its compounds where the concentrations of impurities are greater than 0.03% for W, 0.01% for Ti, 0.005% for Mo, V, 0.003% for Cr, Fe, Nb, Ni, 0.001% for Si, Mn, and 0.0003% for Mg. The coefficient of variation for the analytical result is about 7%. This method is also applicable to the analysis of condenser-grade tantalum powder as well as tantalum for ordinary industrial use.View full abstractDownload PDF (418K) -
Yûnoshin Imai, Toshio Saitô1961 Volume 25 Issue 1 Pages 57-60
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of isothermal heating on the ε-phase formation in solution-treated standard Hadfield steel was studied. When solution-treated Hadfield steel was heated isothermally at some temperature range, it precipitated a large quantity of grain-boundary carbides and pearlitic constituents. Consequently, the carbon content in the γ-phase decreased, then the γ-phase was transformed to ε-phase after the specimens were cooled to room temperature. The isothermal temperature range of steels containing the ε-phase at room temperature shaped a C-curve which has the nose of 500°×5 hr and extending over the temperature range of 450∼625°. This range corresponds to the range in which a large quantity of pearlitic constituents were precipitated. The existence of the ε-phase in steels at room temperature was observed in both the microstructure and the X-ray diffraction pattern. This ε-phase was transformed to the γ-phase when the specimens were heated at 200∼280°,and this transformation was confirmed as a remarkable expansion in the thermal dilatation curve.View full abstractDownload PDF (575K) -
Yûnoshin Imai, Toshio Saitô1961 Volume 25 Issue 1 Pages 61-65
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHadfield steels, isothermally heated at some temperatures, precipitates grain-boundary carbides, platelet carbides and pearlitic constituents. In steels, with the precipitates grown up to large quantity, γ was transformed to ε at about room temperature in cooling, then the ε phase was present with carbides and α in steels. The equilibrium phases of Hadfield steels at room temperature were reported as α+carbide, but the process of phase translation leading to equilibrium is not yet known. In this works, standard Hadfield steels of chemical composition of C 1.2%, Mn 13.71% and isothermally heated at 500° for various durations after solution treatment, were studied mainly dilatometrically and magnetically. At 500°, the γ-phase in this steel was primarily translated to (γ+c), next to (γ+α+c) to (α+c) and to the final equilibrium phase (α+c). But it required a very long time to attain the equilibrium phase. At room temperature, the γ-phase in this steel primarily translated to (γ+c), then to (γ+α+c), to (γ+ε+α+c), to (ε+α+c), to (α+c), and to finally to the equilibrium phase (α+c). The ε-phase in Hadfield steel is apparently a metastable phase which appears in phase translation process to equilibrium.View full abstractDownload PDF (536K) -
Kaizo Monma, Hajime Suto1961 Volume 25 Issue 1 Pages 65-68
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis paper proposes a formula to calculate thermodynamically the surface tension of binary liquid system which forms imperfect solution. According to the author’s experimental results, it is natural to assume that (1) the molecules on the surface are packed at the same mole volume as in the bulk, and (2) the difference of the surface composition from that of the bulk is confined to a single moleculer layer of surface. Then the Bulter’s equation (ψiσ−ψi=γai) can be applied to metallic solution. Furthermore, the following equations can be deduced. (1) In a substitutional type binary system,
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(2) In a interstitial type binary system,
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Equation (1) is similar to Hoar and Melford’s equation, but the Value of 1″ is to be chosen to suit the type of chemical bonding of the liquid, namely 0.5 for van der Waals liquid, 0.82 for metallic liquid and 0.90 for ionic liquid. The interfacial tension is also discussed.View full abstractDownload PDF (313K) -
Tadashi Kawasaki, Takehiko Shibai, Hisashi Izumi1961 Volume 25 Issue 1 Pages 68-72
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electron-microscopic structure of mild steel stress-aged (strain-aged under definite mechanical stresses) at various conditions was examined. The change of structure caused by strain-aging, at 100°C and 200°C for predetermined length of time, was also examined for mild steel which had been stress-aged at various conditions. It was confirmed by electron-microscopic study that the strain aging of mild steel is accelerated without doubt by mechanical stresses imposed on the specimen during the strain-aging so that much more solute atoms in ferrite will be consumed during the stress-aging to produce a great number of fine precipitates. The stress-aged specimens did not show any significant structural change even when they were strain-aged. This means that, after the stress-aging, there is not so many solute atoms in ferrite as may contribute to strain-aging of mild steel. It may be possible to obtain a non-ageable mild steel by utilizing the stress-aging.View full abstractDownload PDF (1239K) -
Tomisaburo Nara, Mikio Nishihata, Masahisa Akiyama1961 Volume 25 Issue 1 Pages 72-75
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of the purity of copper on the Vickers microhardness under a light load of 50 g and its dispersion has been studied with zone-refined polycrystalline copper wires. The results obtained are as follows: (1) The mean values of microhardness measured at 100 points do not depend upon the purity of wires used, but their dispersions become smaller as the purity increases. The standard deviation for the full-annealed 99.999+% specimen is 1.74. (2) With increase of the purity of the specimens, the dispersion of grain-boundary hardness is decreased and the tendency is nearly similar to the dispersion of grain hardness. (3) Comparing the mean values of grain-boundary hardness with grain hardness, it is ascertained that the former is smaller than the latter if the purity of the specimens is 99.999 per cent or more.View full abstractDownload PDF (376K) -
Masayuki Kawasaki, Sueo Nomura, Tatsuo Kondo1961 Volume 25 Issue 1 Pages 76-79
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBy the static autoclave tests at the temperatures up to 200°C, the effect of several factors affecting intergranular attacks of pure Al was studied. The results were: (1) Purity of Al: By the short time tests of 99, 99.9 and 99.99%Al, it is ovserved that the higher the purity of Al, the lower is the corrosion resistance in addition,the severer is the preference of intergranular attack. Particularly, 99%Al is resistant because of its uniform oxide formation. (2) Crystal grain size: In the case of 99.99%Al, a fine-grained specimen is less resistant than a coarse-grained, for the individual boundaries of both specimens are penetrated to the same extent. (3) Atomosphere: Intergranular corrosion is almost suppressed under oxygen atomosphere, while under hydrogen atmosphere, it is promoted. (4) pH of water: The total amount of corrosion is minimized when pH of water is lowered down to 3 and intergranular attacks do not occur under such condition. (5) Cold working: The distribution of slip defects formed by plastic deformation alters corrosion interfaces so that higher rolling reduction causes disappearance of intergranular attack but promotes break-down of oxide. These examinations are extended to the interactions between such defects and atomospheric gases. From the all over results, the corrosion mechanisms are discussed in relation to hydrogen hypothesis.View full abstractDownload PDF (809K) -
Masayuki Kawasaki, Tatsuo Kondô, Sueo Nomura1961 Volume 25 Issue 1 Pages 80-83
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe corrosion behaviours of several kinds of binary Al alloys are obeserved. As specimens, cast ingots and rolled sheets were employed to observe the relationship of corrosion attack and alloy structure. By the corrosion tests at 300°C, these alloys are classified in three categories from their corrosion behaviours. They are, (1) Alloys which are susceptible to the intergranular attack and accordingly do not show any delay in corrosion rate. (2) Alloys which are corroded uniformly and have 2 stages, namely the first stage of low corrosion rate and the second stage of linearly accelerated attack. In the latter step, they do not show intergranular attack but localized penetration on phase boundaries or primary phase. (3) Alloys which have low corrosion rate and never show rate transitions in the range of our testing period. These are the most resistant. The delay before the intiation of the second step in the alloys of category (2) is controlled by alloyed elements and their concentration. It is remarkable that the weight increase of these alloys at steady state is equivalently about 30 mg/dm2 in every alloy. After the corrosion rate transition, crystallization of boemite is observed by X-ray diffraction of corrosion products.View full abstractDownload PDF (611K) -
Osamu Izumi, Hiroshi Fukuda1961 Volume 25 Issue 1 Pages 84-87
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of cold-working (cold-rolling of 30 and 80% in reduction) prior to aging treatment on the aging characteristics of some copper-beryllium alloys was investigated. The experiments were carried out on the binary alloys containing 0.7 and 1.8 wt% beryllium, respectively as well as on the ternary alloys containing additionally 0.3% cobalt. In the aging of cold-worked specimens, it was hardly possible to discriminate the effect of cold working on the aging process from the change in hardness and electrical resistance, because of the simultaneous occurence of recovery, over-aging or recrystallization. However, the change in Young’s modulus showed that the cold-working accelerated the aging process in both low-and high-temperature ranges. Differences in aging characteristics due to the alloy composition and the degree of cold-working were also discussed in relation to the results of microscopic observations.View full abstractDownload PDF (467K) -
Hirozo Kimura, Akira Ito1961 Volume 25 Issue 1 Pages 88-91
Published: 1961
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe binary system platinum-niobium has been investigated by X-ray analysis, microscopic examination and liquidus temperature determination. The platinum phase (α) dissolves up to 36 at%Nb and the lattice parameter of platinum increases from 3.916 kX to 3.956 kX with alloying of niobium. The melting point of α-phase alloy rises with increasing of niobium content and 36 at%Nb alloy shows the maximum rise 2000°C. There are two intermetallic compounds, PtNb2 and PtNb3, in this system. PtNb2 is formed by a peritectic reaction of liquid+PtNb3\ ightleftharpoonsPtNb2 at about 1900°C. PtNb2 has a tetragonal lattice, and forms an eutectic with α-phase of 36 at%Nb at 1700°C. The eutectic composition is 45 at%Nb. Thers is a peritectic reaction between Nb and PtNb3 as follows: liquid+Nb\ ightleftharpoonsPtNb3 at about 2000°C. PtNb3 has a β-wolfram type cubic structure and its lattice parameter increases from 5.137 to 5.156 kX with increasing of niobium. The solubility limit of platinum in niobium is less than 1 at%. 25 at%Nb alloy (correspond to Pt3Nb) has a random array of platinum and niobium atoms on face-centered cubic lattice at high temperature and shows a disordered structure. The formation of a superlattice takes place below a critical temperature, and its temperature is close to the solidus and is estimated as about 1800°C.View full abstractDownload PDF (619K)
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