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Volume 40, Issue 10
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Tatsuji Yamamoto, Yoshio Utsushikawa1976 Volume 40 Issue 10 Pages 975-981
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe crystal magnetic anisotropy constant Kc and the magnetostriction λs of a Sendust alloy in composition of 9.6%Si-5.4%Al-bal.Fe are almost equal to zero. Therefore this alloy shows high permeability, but its brittleness makes the alloy to be hardly rolled. With the object of developing a new alloy having higher permeability and workability, we have made a study of effects of the addition of Ni as a fourth element on magnetic properties of 6%Si-4%Al-bal.Fe alloy showing a second largest value of maximum permeability μm in the Fe-Si-Al system. In this paper the dependence of magnetic properties of 6%Si-4%Al-bal.Fe alloy containing 0 to 7%Ni on annealing conditions and the effects of magnetic field treatment are described in detail. The experimental results obtained are summarized as follows:
(1) Magnetic properties of the 6%Si-4%Al-bal.Fe alloy are remarkably influenced by Ni addition, especially by the addition of 2∼4%Ni the coercive force Hc decreases and then the maximum permeability μm increases considerably.
(2) An alloy in composition of 3.15%Ni-5.33%Si-4.22%Al-bal.Fe was heat-treated under the optimum conditions, that is, annealing at 750°C for 1 hr in hydrogen and cooling to room temperature at a rate of 1.7°C/sec, and the following magnetic properties were obtained: μm=56800, Hc=0.096 Oe, Br=8100 G, Bm=9800 G and Kf=86.6%.
(3) Magnetic properties of the above-mentioned alloy are improved strikingly by heattreatment in a magnetic field. When applying a magnetic field 20 Oe during cooling from 700°C to room temperature after annealing at 1250°C for 1 hr in hydrogen, the following magnetic properties were obtained: μm=165000, Hc=0.03 Oe, Br=9540 G, Bm=10900 G and Kf=87.5%. Therefore, we have named this newly detected high permeability alloy “Super Sendust”.
(4) The values of magnetostriction λs, magnetic moment σs, Curie point Tθ, electrical resistivity ρ and Vickers hardness Hv of the new alloy were affected considerably in the composition range of 2 to 4%Ni.View full abstractDownload PDF (610K) -
Takurô Nakamichi1976 Volume 40 Issue 10 Pages 981-987
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBased on a simplified morphological model of etch pit, various types of light figures are described in mathematical forms. To describe the elements in linear form or with an extended area of light figures in addition to light spots, it is proposed that etch pits, are composed of curved surfaces such as cylindrical, conical and spherical ones, in addition to well-defined crystallographic planes. The mathematical expressions of light figure elements corresponding to these curved surfaces are obtained by geometrical consideration. The light figures expected from these curved surfaces are light arrow, hyperbolic, circular and ellipsoidal arcs, and circular area, which are frequently observed in the studies of light figures. Some examples of such light figure are analyzed by this method.View full abstractDownload PDF (543K) -
Yuri A. Shamanin, Takeo Yokobori, Hiroshi Sakata1976 Volume 40 Issue 10 Pages 988-992
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe static strength and the fatigue strength of Ti-5Al-2.5Sn alloy was investigated.
Heat treatment improves the static fracture strength and the fatigue strength, and increases the ratio τw⁄σwb of reversed torsional fatigue limit τw to reversed bending fatigue limit σwb. Tensile lower and upper yield stresses and ultimate tensile strength increase linearly with respect to the inverse square root of grain size diameter. Elongation, reduction of area and torsional ductility are increased by heat treatment.
The dependence of the endurance limit under different combinations of alternating bending and torsional stresses has been obtained experimentally and compared with the theoretical criterions. The fatigue fracture criterion is given by the maximum shear stress criterion with a small error in the safe side for design use, whereas the criterion for the overal (macroscopic) direction of fatigue crack propagation is given by macroscopic (applied) tensile principal stress. It is to be noted these criterions do not necessarily agree with each other.View full abstractDownload PDF (471K) -
Hiroshi G. Katayama1976 Volume 40 Issue 10 Pages 993-999
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe commercial extra-pure chromic oxide was reduced with powdered graphite (ash content <0.10%) over a temperature range of 990∼1170°C under Ar atmosphere. The reduction rate was measured by means of a thermobalance using a silica glass spring.
The results are as follows:
(1) The reduction took place in three orderly steps, i.e., in periods of incubation, acceleration and retardation.
(2) The incubation period became longer as the temperature was lowered and the particle size of the graphite was increased. In the incubation period, the process of nucleation was rate-determining.
(3) Based on the supposition that the Boudouard reaction was a rate-determining process in the acceleration period, the observed data were analysed kinetically and could be explained satisfactorily.
(4) The reduction products were Cr3C2 and Cr7C3.
(5) In the retardation period, the reaction rate was remarkably lowered. It seemed that the reaction was controlled by the counter-current diffusion of CO and CO2 through a relatively compact layer of chromium carbides.View full abstractDownload PDF (594K) -
Yasuhide Minonishi, Hideo Yoshinaga, Shotaro Morozumi1976 Volume 40 Issue 10 Pages 1000-1009
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe Portevin-LeChatelier effects in commercial-purity titanium have been investigated on specimens of various grain sizes ranging from 6.5 to 180 μm.
The P-L effects are clearly observed in specimens of 25 μm or more in grain size, but they become obscure as the grain size is smaller than 13 μm and almost disappear at 6.5 μm. In specimens of intermediate grain sizes from 25 to 45 μm deformed at a strain rate of 2.8×10−4 sec−1, serrated flow occurs at temperatures from 330 to 440°C. When the grain size increases to 180 μm, a different type of serrations, in addition to the above P-L effect, are observed in a higher temperature range centred at 500°C. Due to these two effects, flow stress shows two separate peaks at the corresponding temperatures in this case.
From the conditions for the onset of serrations, the mechanism is discussed and it is suggested that the P-L effect observed at lower temperatures is due to Snoek atmospheres of oxygen-oxygen and/or oxygen-carbon solute pairs formed around moving dislocations and the one at higher temperatures is due to nitrogen atoms. Absence of the P-L effects in fine-grained specimens is explained in consideration of secondary slip systems forced to be activated by the constraining effect of grain boundaries.View full abstractDownload PDF (997K) -
Yuko Hanatate, Kazuhiko Majima, Hiroyasu Mitani1976 Volume 40 Issue 10 Pages 1010-1015
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUsing Ni-coated Fe powder and Fe-Ni alloy powder, the mechanism of activated sintering with Ni addition was investigated by a dilatometer and autoradiography.
The shrinkage of Ni-coated Fe powder increased with increasing Ni content up to 0.08 wt%. Over 0.08 wt%Ni, the shrinkage became constant, where the slope (rate exponent) measured from the logΔL⁄L0−logt relation was about 0.32.
The activation energy of sintering of the 1.0 wt%Ni-coated Fe powder compacts was about 40000 cal/mol, which is similar to that obtained for the self grain boundary diffusion of Fe.
The results of autoradiography of the radioactive Fe into pure Fe powder and 1.0 wt%Ni-coated Fe powder compacts, confirmed that the presence of Ni in the grain boundaries promoted the grain boundary diffusion of Fe.
Consequently, it becomes clear that the grain boundary diffusion of Fe should play an important role in the activated sintering for the Fe-Ni system.View full abstractDownload PDF (730K) -
Kenji Hatanaka, Toshiro Yamada1976 Volume 40 Issue 10 Pages 1016-1024
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe rotating bending high cycle (cyclic frequency: f=50 Hz) and the push-pull low cycle (f=0.2 Hz) fatigue tests were performed, and the grain size dependence of the fatigue strength was examined for the solution-treated Al-2.4%Mg Alloy.
The fatigue strength of the plain specimen depends on grain size in the long life range, while in the short life range it is almost independent of grain size. Such a grain size dependence, which is in contrast with that of copper and aluminum, is discussed from the strain ageing effect and the behavior of initial fatigue cracks.
The fatigue life of the notched specimen is scarcely affected by grain size. This can be attributed to that a great percentage of fatigue life is occupied by the non-crystallographic fatigue crack propagation process in the same way as other metals. Moreover, a non-propagating crack is always formed in the notched specimen stressed cyclically up to about 2×107 cycles at the stress amplitude corresponding to the fatigue limit. This crack developes through the crystallographic path around the circumference of the notch root, but it stops at a depth of about 50 μ independently of grain size.
The low cycle fatigue life controlled by the plastic strain range is almost independent of grain size. Therefore, the low cycle fatigue life does not always correspond to the fracture ductility influenced by grain size. This might result from that the defects such as inclusion and void are contained in the test material and the fatigue induced plastic deformation is localized in the vicinity of the grain boundary.
The shapes of S-N curves suggest that the fatigue limits exist both in the plain and notched specimens. The dynamic strain ageing induced by cyclic stressing might contribute to the formation of the fatigue limit.View full abstractDownload PDF (1540K) -
Mineo Kosaka, Tadashi Asahina, Hiroshi Hayashi1976 Volume 40 Issue 10 Pages 1024-1030
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEquiribrium partial pressure of various chemical species in acetylene-nitrous oxide (C2H2-N2O) gas flame for atomic absorption analysis has been determined by the use of an iterative computer technique based on a thermodynamic model. Calculations were carried out for N2O/C2H2=1.2∼3.0, in the temperature range between 2000 and 4000 K and effects of water (H2O), which was sprayed into the flame as the solution of metals to be analysed, was taken into consideration.
The results was indicated that the free-atom fractions β calculated for various metals varied with the N2O/C2H2 ratio and with the rate of water spraying. Normalized values for free-atom fraction, (β⁄β1.2), agreed fairly well with the normalized absorbance, (I⁄I1.2), determined experimentally using an atomic absorption analyser, where β1.2 and I1.2 were the values obtained at N2O/C2H2=1.2.View full abstractDownload PDF (545K) -
Akio Kasama, Takamichi Iida, Zen-ichiro Morita1976 Volume 40 Issue 10 Pages 1030-1038
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to discuss the temperature dependence of surface tension of liquid pure metals, the surface tension of Cu, Ag, Au, Sn and Pb in the liquid state has carefully been measured by the sessile drop method in an atmosphere of prepurified hydrogen or argon, with a partial oxygen pressure of about 10−20 atm, over the temperature range between the melting points and 1450°C. The surface tension of their metals decreased linearly with increasing temperature over the entire temperature range irrespective of the kinds of atmospheric gas. Furthermore, based on the data obtained in the present experiment and a previously established theory of surface tension of liquid pure metals at temperatures close to their melting points, a consideration was made to account for the temperature dependence of surface tension of liquid pure metals from the phenomenological standpoint and an simple equation for the temperature change of surface tension of liquid pure metals was derived in terms of the atomic volume (or density) as a parameter: γ\simeq\frac12 ·\fracπ^2β^2C^2T_mN \frac{(1+α)V_m^1/3-V_T^1/3}^2V_T^4/3
It was shown that the values of surface tension calculated by the above equation were in good agreement with a series of experimental values obtained in the present work and by other investigators.View full abstractDownload PDF (756K) -
Kimio Itagaki1976 Volume 40 Issue 10 Pages 1038-1046
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBy using a double adiabatic wall calorimeter, the heat of fusion and specific heat of the seven gold compounds of AuGa, AuGa2, AuIn, AuIn2, AuSn, AuSb2 or AuTe2 were determined.
Equations for the excess integral free energy of mixing ΔGE of liquid binary alloy systems involving stoichiometric compounds, were derived as a function of heat of fusion of the compound and the liquidus coexisting with the compound. From the obtained data and the derived equations, ΔGE of the liquid gold binary alloys of Au-Ga, Au-In, Au-Sn, Au-Sb or Au-Te were calculated, and it was clarified that the calculated values depend basically on the accuracy of the liquidus.View full abstractDownload PDF (732K) -
Yutaka Nakayama, Taichiro Ito, Hiroshi Mabuchi, Tadashi Kitsudo1976 Volume 40 Issue 10 Pages 1046-1052
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSingle crystals of Cu-6.5 at%Si alloy having various orientations have been deformed in tension at room temperature and 77°K. In particular, the deformation of easy glide in the crystals oriented for single slip have been investigated by optical microscopy, replica and transmission electron microscopy. The results obtained are as follows.
(1) The plastic deformation of stage I occurs by a typical Lüders band-type propagation of the coarse slip bands. When the propagation is completed along the length of the crystal, stage I comes to an end and then stage II hardening appears.
(2) The slip band structure observed by replicas changes with deformation temperature. Spacing between slip bands at room temperature is wider than that at 77°K. On the other hand, step heights of slip bands coming most frequently at room temperature and 77°K are about 600 and 400 Å, respectively.
(3) The main feature of the dislocation structures in stage I is the arrangement of large groups of primary dislocation aligned in a single slip plane or in a few closely spaced neighbouring slip planes. Most of the dislocations lying on closly spaced neighbouring slip planes take a form of dipole clusters.
(4) During the easy glide, a few twin bands appear at the front region of Lüders band-type deformation; and it takes place on the primary slip plane.View full abstractDownload PDF (1393K) -
Kiyohiko Nohara, Ken-ichi Hirano1976 Volume 40 Issue 10 Pages 1053-1061
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSImpurity diffusivities of Mo in pure Fe in the temperature range of 710 to 1300°C and the self-diffusivities of Fe and Mo in Fe-Mo alloys in the temperature range of 1000 to 1300°C have been determined by the residual activity method using the radioisotopes, Fe59 and Mo99.
Effects of both the α-γ phase transformation and the magnetic transformation on the temperature dependence of the diffusivity of Mo in pure Fe have been observed. The results on the self-diffusion of both Fe and Mo in Fe-Mo alloys show a minimum diffusion coefficient and corresponding to this, a maximum activation energy and a frequency factor in the ε phase.
Concentration dependence of the self-diffusivities in the α solid solution and in the two-phase (α+ε) alloys were quantitatively discussed. Further, through investigating the data on the impurity diffusion of various elements in α-Fe and γ-Fe including the present result, an empirical equation was proposed to correlate the activation energy for diffusion with the atomic volume of diffusing atom and excess valence of impurity.View full abstractDownload PDF (815K) -
Kei Matsui, Akira Matsuno, Fumio Kizu, Mutsumi Takahashi, Hideo Kanno1976 Volume 40 Issue 10 Pages 1062-1068
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFlaky graphite cast irons with the high damping capacity have been used for the control of vibration and noise occurring in the members of various mechanical structures under vibrating conditions. However, the damping capacity which is independent of amplitude is one of the important factors in reducing the vibration and noise, but almost no work has delt with this problem.
Therefore the authors have examined the amplitude dependence of the damping capacity of various cast irons with carbon equivalent of 3.8% up to 4.8% and studied the influences of the matrix, the carbon equivalent and the graphite microstructure upon the damping capacity of the amplitude independence. The main results obtained are as follows:
(1) The damping capacity of cast irons in the region of low strain-amplitude is independent of the strain amplitude and increases with the carbon equivalent. In the region of high strain-amplitude, however, the dependence on strain-amplitude increases as the carbon equivalent increases.
(2) The damping capacity of the strain-amplitude independence increases as the carbon equivalent increases and changes remarkably when the carbon equivalent approaches the eutectic composition. This is due to the continuity of graphite, which is explained by the fact that the damping capacity of graphite-removed cast irons becomes very low.
(3) It may be concluded that the damping capacity of flaky grahite cast irons results from the energy loss due to the stress distribution in graphite itself, related to the graphite continuity.View full abstractDownload PDF (992K) -
Han-ryong Pak, Toshio Saburi, Soji Nenno1976 Volume 40 Issue 10 Pages 1068-1074
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of Co addition up to 1.5 at% on the temperature dependence of yield stress in Ni3Ge with L12 structure has been investigated. Flow stress measurements were made on (Ni, Co)3Ge single crystals with several different orientations. Slip systems were determined by two-surface trace analysis after compression at various temperatures between −196 and 600°C. Comparing the result of (Ni, Co)3Ge with that of the binary Ni3Ge, we obtained the following conclusions: The mechanical behavior of (Ni, Co)3Ge is essentially the same as that of the binary Ni3Ge. However, the Co addition lowers the maximum-yield stress temperature of the binary Ni3Ge at which the slip system changes from (111)[\bar101] into (001)[\bar110]. The drop of this temperature is orientation-dependent and governed by the relative change in critical resolved shear stress between the (111)[\bar101] slip system and the (001)[\bar110] slip system due to Co addition.View full abstractDownload PDF (1277K) -
Masateru Suwa, Katsuhiro Komuro, Kô Soeno1976 Volume 40 Issue 10 Pages 1074-1081
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMethods for uniform dispersion of graphite particles in Al-Si melts, and mechanical properties and wear resistance of graphite-dispersed Al-Si alloys have been investigated. The weight per cent of graphite varied from 2.1 to 17.4%.
Uniform dispersion of graphite particles was obtained by adding nickel-coated graphite particles into the melts. Gas hole formation during the solidification of the melts was suppressed under a pressure of about 560 kg/cm2.
Two series of graphite-dispersed Al-8%Si and Al-12%Si alloys containing 3%Cu, 0.3%Mg and less than 5.6%Ni were used for the investigation of mechanical properties and wear resistance.
Although the strength and elongation in this alloy system decreased with increasing graphite content, even the alloys containing 17.4 wt% graphite seemed to be capable of industrial use.
Under dry friction, the wear resistance of the alloys increased with increasing graphite content. The wear rate of the alloys containing 17.4 wt% graphite was about 10−8 mm3/mm·kg, which was nearly equal to that under lubricated friction of the graphite-free base alloys. Under lubricated friction, the wear resistance of the alloys increased over the composition range of 5 to 10 wt% graphite. However, the wear resistance decreased in the alloys containing graphite in excess of the amount which gives the maximum wear resistance. It was also found that the graphite content corresponding to the maximum wear resistance increased with increasing strength of the alloys, or with decreasing load in the wear test.View full abstractDownload PDF (1460K) -
Kenzo Kon, Namio Ohtani1976 Volume 40 Issue 10 Pages 1082-1087
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStress corrosion cracking (SCC) of α-brass single and bicrystals in an ammoniacal atmosphere was examined with regard to applied stress, the orientation of the tensile axis and the misorientation of grain boundary. The results obtained are as follows:
(1) The time to fracture of single crystals decreased with the increase of applied stress. The specimens of a larger Schmid factor fractured more rapidly than the specimens of a smaller Schmid factor under the same applied stress.
(2) The shear stress in the slip direction on a slip plane more remarkably affected the time to fracture than that normal to a slip plane did. This means that SCC of single crystals occurs by slipping at the tip of crack.
(3) As far as single crystals are concerned the crackings occurred in general along (111) traces having a maximum Schmid factor, but the crackings were also observed along the traces of secondary slip planes and cross slips when the applied stress became higher.
(4) In bicrystals, fracture occurred generally in the grains when tilt and twist angles of grain boundaries were small, and at grain boundaries when these angles were large. In some bicrystals, however, fracture occurred in grains or at grain boundaries regardless of the degree of the misorientation of grain boundaries.View full abstractDownload PDF (579K) -
Kazuo Kameda, Takeshi Azakami1976 Volume 40 Issue 10 Pages 1087-1092
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe values of E.M.F. of liquid Au-Ga and Au-Bi systems were measured in the temperature ranges from 670 to 820°C and 670 to 850°C by using galvanic cells composed of
(This article is not displayable. Please see full text pdf.)
\ oindentrespectively.
The values of E.M.F. obtained for the Au-Bi system showed a good stability and a linear relationship with temperature.
While the values obtained for the Au-Ga system were somewhat unstable and showed less reliability than those for the Au-Bi system.
The activities of both components for the Au-Ga system demonstrate a considerable negative deviation from Raoult’s law over the whole concentration range. As for the Au-Bi system the activities of both components show a slight negative deviation from Raoult’s law over the entire range of concentration.
The maximum values of the heat of mixing are −2.20 kcal/mol for the Au-Ga system at NGa=0.48 and −0.18 kcal/mol for the Au-Bi system at NBi=0.55.
The activity coefficients of gallium in the liquid Au-Ga alloys are represented by the relation
(This article is not displayable. Please see full text pdf.)
\ oindentIntegration of the Gibbs-Duhem equation yields the relation
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\ oindentConsequently, the excess molal free energy of mixing is given by the relation
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (424K)
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