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Volume 35, Issue 9
Displaying 1-20 of 20 articles from this issue
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The Solubility of Nitrogen and the Equilibrium of Nb-Nitride Forming Reaction in Liquid Fe-Nb AlloysZen-ichiro Morita, Kunio Hachisuka, Yuji Iwanaga, Akira Adachi1971 Volume 35 Issue 9 Pages 831-839
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSolubility of nitrogen and equilibrium of Nb-nitride forming reaction in liquid Fe-Nb alloys under the presense and the absence of Nb-nitride were measured by the sampling method at 1600°, 1650° and 1700°C in the concentration range of 0∼30%Nb, and the behaviors of niobium and nitrogen were thermodynamically discussed through these experimental results.
The solubility of nitrogen markedly increased with increasing niobium concentration in liquid alloy in the absence of Nb-nitride, and it decreased with increasing temperature especially at a higher concentration of niobium. On the other hand, it decreased with increasing niobium concentration in the presense of Nb-nitride. The interaction coefficient of niobium, fN(Nb) can be expressed as a function of niobium concentration at each temperature as follows:
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The Nb-nitride appeared in the liquid Fe-Nb-N system was confirmed to be a hexagonal and cubic NbN by Debye-Scherrer X-ray diffraction analysis. The standard free energy of decomposition of NbN was determined to be
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The self-interaction parameter of niobium, eNb(Nb) was also estimated as zero. The empirical equations for estimating the solubility limit of niobium when the nitride begins to form in liquid Fe-Nb alloys under a given nitrogen pressure were obtained as follows:
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Masayuki Tsuchiya, Masao Izumiyama, Yunoshin Imai1971 Volume 35 Issue 9 Pages 839-845
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe specific heat of the supercooled γ-phase and the free energy difference between α- and γ-phases of iron at each temperature were investigated. As γ iron is not stable below 910°C, it is impossible in principle to obtain the specific heat without some reasonable presumptions. In the present study, specific heats of γ-phases of several Fe-Ni and Fe-Mn binary alloys were determined at various temperatures by using an automatic specific heat measurement apparatus of the adiabatic type, and the results were extrapolated to pure iron. From thermodynamic data, calculated from the specific heat of the γ-phase of iron, the free energy change in the α-γ transformation of iron at each temperature was determined and that of the α-phase was considered to be most reliable.View full abstractDownload PDF (2327K) -
Masaaki Tanihara1971 Volume 35 Issue 9 Pages 846-853
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe indentation figure on single crystals of Al is a deformation marking which consists of a pit bored on the specimen surface by the indenter, groups of slip bands, and the undulation and the fold of material around the pit. In order to clarify the mechanism of slip bands formation by indentation, the author examined the relationship between the appearance of slip bands and the values of the cosχcosλ (Schmid factor) for all 12 slip systems which are calculated for 36 directions of applied forces being perpendicular to the surface of the conic indenter (apex angle 30°).
It is shown that the Schmid factor is considered to be important for the activation of slip in some cases but not so in other cases. This is explained in terms of geometrical factors for the slip plane and the slip direction.
In conclusion, the Schmid factor is important for the activation of slip. Further, the additional radial compressive stress along the specimen surface, which is thought to cause the bending and elevation of the material around the pit, seems to play an important role.View full abstractDownload PDF (3283K) -
On the Formation Process and Dislocation Reactions of Conical Indentation on the Cube Face of CopperShozo Yoshioka, Mitsuo Mera, Eiichi Sukedai1971 Volume 35 Issue 9 Pages 854-859
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe formation process of indentation with a conical indentor is studied on the cube face of Cu single crystals. The nature of the dislocations and their interactions involved in formation of the indentation are discussed in reference to the Dyer’s results on the ball indentation and the comprehensive analysis by Hirth of the dislocation interactions in fcc metals. The results obtained are as follows:
(1) The deformation process of the indentation with a conical indentor may proceed accompanying two elemental processes; the dislocation on convergent slip planes are operated by the semi-spherical apex of indentor, and divergent slip planes by the conical side.
(2) The square-like dislocation clustering zone seems to be formed by the interactions of dislocations on convergent slip planes and the fork-like one by the interactions of dislocations on convergent and divergent slip planes, respectively.
(3) It is assumed that the sessile dislocations in the square-like and fork-like dislocation clustering zones are the stair-rod dislocations having the Burgers Vectors of a⁄3·⟨100⟩ and a⁄6·⟨013⟩, respectively.View full abstractDownload PDF (2577K) -
Toru Yokoyama, Takasi Takezawa1971 Volume 35 Issue 9 Pages 860-865
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrical resistivity of the Fe-Co alloys containing up to 70 at%Co is measured as a function of quenching temperature and isothermal annealing time. The resistivity is measured at liquid nitrogen temperature. In the resistivity versus quenching temperature curve, the resistivity of 5∼20 at%Co alloys increases slightly with reducing temperature. The resistivity of 25∼70 at%Co alloys shows an upward or downward winding with reducing temperature. The temperature of winding corresponds to the order-disorder transition temperature, Tc. The resistivity at temperatures above Tc of 33.3∼70 at%Co alloys shows an almost constant value for the disordered state. The increase of resistivity below Tc appears most strikingly in the 33.3 at%Co alloy.
The resistivity of the alloys quenched from 800°C increases rapidly up to 17.5 at% with increasing cobalt content and then decreases conversely to 70 at%. The resistivity of the alloys quenched from 450°C shows a maximum value at 17.5 at%Co and a minimum value at 50 at%Co. From the isothermal annealing curve of the disordered alloys, the activation energy for ordering of 33.3, 40, 50 and 60 at%Co alloys is determined respectively as 61, 54, 51 and 45±2 kcal/mol.View full abstractDownload PDF (2160K) -
Relation between Heat Treated Microstructures and the Equilibrium Diagram in Various Titanium AlloysShoichi Tokuda, Hiromichi Kawahara1971 Volume 35 Issue 9 Pages 865-870
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSeven commercial titanium alloys were classified according to the equilibrium diagram and metallography in comparing the β stabilizing degree which can be obtained from the results of X-ray diffraction and observations of the optical and electron micrographs (surface replica) under various heat treatment conditions.
(1) The β stabilizing degree decreases in the order of Ti-13V-11Cr-3Al, Ti-16V-2.5Al, Ti-4Al-3Mo-1V, Ti-5Al-2Cr-1Fe, Ti-6Al-4V, Ti-8Al-1Mo-1V and Ti-5Al-2.5Sn.
(2) In the classification of titanium alloys according to the equilibrium diagram and metallography, it seems most appropriate to classify the alloys into two kinds for the strong β stabilized alloys, two for the weak β stabilized alloys and one for α alloys, that is, five kinds all together.View full abstractDownload PDF (2180K) -
Katsutoshi Ono, Akio Yamaguchi, Joichiro Moriyama1971 Volume 35 Issue 9 Pages 871-877
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe purpose of this study was to establish the relationship between thermochemical properties, composition and defect structure of Wustite.
The atomic ratios of oxygen to iron in various compositions of Wustite were determined in the temperature range of 685°∼1300°C at various mixtures of CO2-H2 by means of thermogravimetry.
By the use of these data, the limits of stability of Wustite and the diagram showing the relationship between oxygen partial pressure, temperature and deviation from stoichiometry in the Wustite phase field were obtained.
The data show a continuous introduction of iron vacancies as oxygen is introduced into Wustite. The value of n in the isothermal oxygen pressure dependence, PO21⁄n, of the weight change shifts to a higher value as the concentrations of oxygen increase.
The defect structure model of Wustite consistent with these findings were discussed in terms of defect complexes such as two vacancies of doubly charged iron ion associated with an interstitial cation with triple charge.
In addition, thermodynamic quantities, such as free energies, entropies and enthalpies of solution of oxygen into Wustite were evaluated.View full abstractDownload PDF (2343K) -
Minoru Nemoto, Tomoyoshi Oguchi, Hajime Suto1971 Volume 35 Issue 9 Pages 878-885
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe formation of point defects, their subsequent aggregation and effects on the recovery process in thin foils of nickel and a nickel-copper alloy have been investigated in a 500 kV electron microscope at a maximum beam current of 0.75 A/cm2 using a specimen heating stage. Dislocation loops and small black dots appeared only after heating above room temperature. Faulted dislocation loops were formed in an extra-pure nickel while prismatic loops in the nickel-copper alloy. The large loops were interpreted as an interstitial type in character from contrast experiments. Higher densities of dislocation loops were formed in a commercially pure nickel and the nickel-copper alloy. Deformation also assisted the formation of dislocation loops. Electron radiation damage accelerated the rate of annihilation of dislocations in deformed foils. Dislocations climbed into helices in the deformed nickel-copper alloy during irradiation and heating.View full abstractDownload PDF (4137K) -
Minoru Nemoto, Tomoyoshi Oguchi, Hajime Suto1971 Volume 35 Issue 9 Pages 886-891
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitation phenomena in thin foils of aluminium alloys have been investigated in a 500 kV electron microscope. During heating of a thin foil of an aluminium-1.4 wt% silicon alloy, a large number of dislocation loops were formed in the area exposed to electron irradiation. These dislocation loops were grown during heating and irradiation and finally the dislocation density in the exposed area was extremely increased. The nucleation of silicon precipitates was also remarkably affected with irradiation. That is, fine distribution of precipitates was observed in the exposed area. The width of precipitation free zones near grain boundaries was decreased with increasing electron irradiation. The growth rate of γ′-precipitates in an aluminium-5.5 wt% silver alloy was almost unaffected by electron irradiation. The formation of misfit dislocations at the coherent interface of θ′-precipitates in an aluminium-4 wt% copper alloy was promoted by electron irradiation. The roles of interstitials and vacancies produced by electron irradiation on the above-mentioned phenomena are discussed.View full abstractDownload PDF (3117K) -
Kazuo Kawamura, Shiro Watanabe, Tokio Suzuki1971 Volume 35 Issue 9 Pages 891-896
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to establish a method for phase analysis of niobium, a study has been made on the chemical behavior of niobium compounds in low carbon steel. Extraction of niobium compounds from low carbon steel was effectively carried out in the cold nitric acid solution. Neither hydrochloric acid(1+1)nor I2·methyl alcohol(10%)methods gave good results for extraction of the niobium intermetallic compound(Fe2Nb)in steel.
The recommended procedure for phase analysis of niobium in the low carbon steel is as follows:
(1) Sample is decomposed in cold nitric acid(1+1)at −20°C.
(2) The extracted residue is filtered and treated with NH4F·HF under heating; niobium as an intermetallic compound is determined in the solution.
(3) The residue of(2)is filtered and treated with NH4F·HF and H2O2 under heating; niobium as carbonitride is determined in the solution and niobium as an oxide is in the insoluble residue.
Separation of fine and coarse precipitates of carbonitride in the cold nitric acid extract was most favorably performed by NH4F·HF treatment.View full abstractDownload PDF (1893K) -
Kozo Kishi, Hiroshi Eda1971 Volume 35 Issue 9 Pages 896-901
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the previous paper, it was investigated the effect of carbon content in steels to make clear machinability factors which affect significantly cutting results such as residual stress and produced structure in the machined surface layer. This paper describes the effect due to grinding force and grinding temperature for the produced structure in the grinding surface layer. Furthermore, the grinding temperature distributions in the workpiece and the thermal residual stresses in the grinding surface layer are discussed. The grinding temperature distributions and thermal residual stresses were investigated by using the finite element method. It was shown that with increasing cementite content, the thermal residual stress and plastic flow in the grinding surface layer decreased gradually. And the increase in the volume fraction of lamellar cementite exerted an influence of raising the thermal residual stress in the grinding surface layer toward the compression side. In the layer, the thermal residual stress calculated by using the finite element method was tensile in the grinding surface. On the contrary, in the inner layer it was a small compressive stress. The residual stress measured by X-rays was tensile in the grinding surface of the layer, while in the inner layer it was a small compressive residual stress. On the other hand, the plastic flow in the layer was produced mainly by the grinding force effect.View full abstractDownload PDF (2082K) -
Shôtaro Shimizu, Eigô Hashimoto1971 Volume 35 Issue 9 Pages 902-907
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe order-disorder transformation in the PtFe-PdFe and PtFe-PtNi alloys were studied in order to evaluate their possible permanent magnetic properties. The quasi-binary alloys Pt50−xPdxFe50 and Pt50Fe50−xNix were prepared by powder metallurgy. The atomic ordering transformation temperature, the magnetic transformation temperature and the lattice parameters were determined. After various heat treatments, the magnetization and coercive force were measured and the possible permanent magnetic properties were discussed. The results are summarized as follows:
(1) Both the quasi-binary systems form the continuous solid solutions, and undergo the transformation from the disordered face-centered cubic structure to the ordered face-centered tetragonal structure of the AuCu I type.
(2) In order to intercept the ordering transformation by water quenching, it is necessary to contain more than 20 at%Pd or 30 at%Ni for these alloys respectively.
(3) In the alloys containing more than 20 at%Pd, the magnetic hardening phenomena are observed through the aging process after water quenching, having sufficiently high saturation magnetization. Thus these alloys are very interesting from the viewpoint of permanent magnetic alloys.
(4) In the alloys containing more than 30 at%Ni, useful permanent magnetic properties cannot be expected because the magnetic transition temperature falls to near room temperature and the saturation magnetization is lowered.View full abstractDownload PDF (1810K) -
Yasuhiko Hashimoto1971 Volume 35 Issue 9 Pages 908-914
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFused-salt electrolysis was carried out in a NaCl-KF-K2TiFx bath at 850°C using a sintered TiC soluble anode prepared by vacuum carburization of TiO2 (pitch was used as the mixing agent of TiO2 and C) at constant anodic potentials from +800 to +1800 mV vs. Ti. The results are summarized as follows:
(1) Maximum values of both the extraction ratio and the current efficiency were obtained at an anodic potential of +1400 mV vs. Ti.
(2) From the anodic polarization of the electrolyte using graphite and the TiC anode, it was estimated that the dissolution of Ti from TiC proceeds by the reaction of TiC and Ti4+ which was formed by the anodic oxidation of Tin+, ie.,
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(3) Current efficiency of dissolution was generally high at the beginning of extraction, but it dropped with the advance of electrolysis, and this drop seemed to be caused by the oxidation-reduction current of the electrolyte.View full abstractDownload PDF (2505K) -
Shinobu Matsushima, Tadao Ishihara1971 Volume 35 Issue 9 Pages 914-919
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of ferrite forming alloying elements such as Mo, Nb, V, Si, Al and Ti on stress corrosion cracking of austenitic stainless steel in boiling 42%MgCl2 solution were studied using U-bend specimens. Time io failure of steels can be devided into two parts, i.e., the first part is the induction period necessary to initiate cracks and the second part is the time to cause fracture. No parallel relationship was found between the time to initiate cracks and the time to fracture. For example, the alloys added V, Si or Al showed long life time to fracture although the cracks initiated in relatively short times. Initiated cracks of these alloys at the austenitic phase were stopped at the interface of δ-ferrite and austenite, and no further propagation was observed. On the other hand, in the cases of the alloys containing Mo, the initiation and propagation of cracks occurred in a short period. The cracks propagate along the boundaries of austenite and δ-ferrite and no stopping effect of ferrite was noticed.
The alloy containing Ti did not crack in a testing period of 50 hours.
All duplex alloys did not crack in the tensile specimens to which a lower stress than that for the U-bend specimens was applied.View full abstractDownload PDF (1695K) -
Kensuke Oki, Masayuki Hasaka, Tetsuo Eguchi1971 Volume 35 Issue 9 Pages 919-924
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanism and kinetic behaviours of ordering in Fe3Al alloy have been investigated by means of X-ray diffraction. The size of the ordered domain was small near the critical temperatures for transformation disorder\ ightleftharpoonsB2 and B2\ ightleftharpoonsDO3, while it was much larger below those temperatures. The variation in the degree of order with quenching temperature was in good agreement with the theoretical results obtained from Bragg-Williams approximation below the critical temperature for the transformation B2\ ightleftharpoonsDO3. The isothermal ordering in quenched Fe3Al was caused by the nucleation and growth of DO3 domains in the B2 matrix. The activation energy for isothermal ordering was 37 kcal/mol. The observed broadening of the 440 normal line on annealing supported that the ordering was due to the heterogeneous process.View full abstractDownload PDF (1766K) -
1971 Volume 35 Issue 9 Pages 924
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:Fig. 6, [in Japanese] Right:[Please see pdf], [in Japanese]View full abstractDownload PDF (19K) -
Tasaburo Nishioka, Yukio Yasukuni, Takeshi Nishioka, Takao Asai1971 Volume 35 Issue 9 Pages 925-929
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDiese Untersuchung ist durchgeführt worden, um die Eigenschaften des Stahldrahtes beim durchlaufenden Warmbiegeverarbeiten mit verschiedenen Querschnittsabnahmen zwischen Raumtemperatur und 400°C zu finden. Von diesen Versuchsergebnisse ist es gefunden worden, dass der Durchmesser des warmbiegeverarbeiteten Stahldrahtes in gleicher Biegebedingung mit steigender Biegetemperatur und zunehmendem Gegenzug abnimmt. Der warmbiegeverarbeitete Stahldraht zeigt die maximale Zugfestigkeit und Streckgrenze sowie die minimale Dehnung bei Biegetemperatur von 200°C. Mit steigender Biegetemperatur nehmen die Zugfestigkeit und Streckgrenze ab und nimmt die Dehnung zu. Ferner lässt das andere Versuchsergebnis die beträchtliche Zunahme der Streckgrenze und die Abnahme der Dehnung mit wachsendem Gegenzug bei Warmbiegeverarbeiten von Stahldraht erkennen. Der warmbiegeverarbeitete Stahldraht hat grössere Zugfestigkeit und Dehnung als der bei gleicher Querschnittsabnahme kaltgezogene angelassene Stahldraht bei Behandlungstemperatur von 200° bis 300°C. Wir denken, dass die ausgezeichnete Eigenschaften von bei Temperatur von 200° bis 300°C warmbiegeverarbeiteten Stahldraht durch die zusammenfügenden Wirkungen von Blausprödigkeit, Bauschinger Effekt sowie von Verfestigung wegen der Zunahme der Zahl der Versetzungslinien beim Warmbiegen gelungen wird.
Man ersieht aus dieser Untersuchung, dass der durchlaufend warmbiegeverarbeitete Stahldraht die ausgezeichneten Eigenschaften durch günstige Biegetemperatur und Verformung beim Warmbiegen zeigt.View full abstractDownload PDF (1508K) -
Michio Ohta, Sadakichi Kitajima, Katsunosuke Aoyagi, Hiroya Kaieda1971 Volume 35 Issue 9 Pages 929-936
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDislocation motion, multiplication and distribution in a highly perfect copper crystal were studied by means of etch-pit technique before and just after yielding. Under the shear stress level lower than 4 g/mm2, the dislocation mobility and the moving distance both decreased with increasing the stress level. On the other hand, their stress dependence was reversed at a stress level higher than 5 g/mm2. The “quasi-multiplication” of dislocation was observed at the stress between 7 and 8 g/mm2. Actual dislocation multiplication occurred at the yield stress of 9.3 g/mm2 in an avalanche-like manner, where the stress-strain curve bent distinctly.
It is concluded that the yield stress of the highly perfect crystal is controlled by cross-over of the dislocation dipoles formed previously, of which the height corresponds to that of giant jogs in the as-grown crystal.View full abstractDownload PDF (3017K) -
Hisashi Suzuki, Kozi Hayashi, Osamu Terada1971 Volume 35 Issue 9 Pages 936-942
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe purpose of this paper is to make clear the mechanisms and the processes of formation of surrounding structure (s.s.) around TiC grains in sintered TiC-Mo2C-Ni alloy. The partial 1300°C isothermal section of the quasi-ternary high carbon alloy was studied. Referring to this diagram, metallographic studies mainly on the coarse-grained alloys having various compositions and sintered under various conditions were made in detail.
Results obtained were as follows: (1) The fromation of s.s.occurred through two or three steps, according to the alloy composition, sintering temperature and time, sintering method, etc. For instance, when the alloys with comparatively high contents of Mo2C and Ni were sintered as usual, there could be observed three steps in the following order: the step of precipitation of Mo2C-25%TiC solid solution (accompanied by the dissolution in particular of Mo2C-2%TiC solid solution) on the surface of TiC grains; the step of solution-reprecipitation of s.s.and TiC core (bared as a result of dissolution of s.s.); and the step of precipitation during cooling. (2) Interdiffusions in or through the carbide phase during sintering seemed in general not to associate with the growth of s.s.and its composition changes. (3) Therefore, the s.s.was generally consisted of two or three layers of different thickness and compositions.View full abstractDownload PDF (2821K) -
Masanori Okada, Makoto Kassai, Yuichi Suzuki, Tatsuji Sasaki, Zenzo He ...1971 Volume 35 Issue 9 Pages 942-946
Published: 1971
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of chemical composion on properties was investigated in high Co-Fe-Nb semihard magnetic alloys. Magnetic properties, resistivity, Vickers hardness, X-ray diffraction and thermal expansion coefficient were measured in the specimens annealed at 500°∼1100°C after cold drawing by 90% reduction in area. The coercive force (Hc) of the specimen with Nb was remarkably increased by the annealing near 700°C and the value of the alloy with 4 wt%Nb reached about 30 Oe. Moreover, a squareness ratio (Ir⁄I100) higher than 0.90 and a magnetization (4π I100) about 16000 G were obtained. The values of squareness ratio and remanence of specimens containing more than 15 wt%Fe in the cold drawn state were low. However, the values increased with the annealing temperature and reached over 0.90 and 14500 G by 700°C annealing, respectively. The crystal structure of Co-21 wt%Fe-3 wt%Nb alloy in the cold drawn state was bcc and transformed to the fcc phase by annealing above 900°C.View full abstractDownload PDF (1443K)
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