All issues
Volume 40, Issue 7
Displaying 1-17 of 17 articles from this issue
- |<
- <
- 1
- >
- >|
-
Nobuo Mikuriya, Takao Takasaki, Hiroyuki Yokoyama, Masato Okochi1976 Volume 40 Issue 7 Pages 657-662
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn experimental study has been carried out to investigate the contribution of basal and nonbasal dislocations (forest dislocations) to the early stage of basal glide in 99.999% pure zinc single crystals compressed at room temperature. The relation between the basal shear stress and the shear strain was plotted and the increase of dislocation density during deformation was observed by means of the etch pit technique. The initial dislocation etch pit densities of the specimens used were 2.9×104∼3.7×104/cm2 on (0001) surface and 6.1×104∼5.2×105/cm2 on (11\bar20) surface. From these data, the length of basal and nonbasal dislocations per unit volume was calculated using equations developed by G. Schoeck. It was assumed that the density of forest dislocations did not change during the deformation since the critical resolved shear stresses for nonbasal slip systems are considerably higher than the stress employed in the experiments. The results obtained were as follows.
(1) The multiplication stresses were approximately equal to the stresses required to break up the attractive junctions between basal and forest dislocations. (2) The yield stresses were represented by the sum of the stress necessary for the forest cutting and the internal stress due to the basal dislocations. From this result, it was concluded that the yield stress, was controlled by the forest cutting under the internal stress field of the basal dislocations.View full abstractDownload PDF (638K) -
Takao Takase, Yasuhiko Nakamura, Makoto Sumitomo, Kiyoshi Kita, Hyoe O ...1976 Volume 40 Issue 7 Pages 663-669
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIron binary alloys containing Al, Cr, Ti, Mo, Si and Mn which were important elements for nitriding were prepared and ion nitrided under several different conditions. Specimens nitrided were examined with respect to the microstructure, hardness and composition of compound layer. The results obtained were as follows:
(1) Al, Cr and Ti formed nitride by nitriding and contributed to the hardening of the diffusion zone. By Mo, Si and Mn additions, however, iron nitrides were mainly formed and the increase in hardness was not so remarkable.
(2) Diffusion coefficient of nitrogen for ion nitriding was calculated on the basis of the hardness distribution curve. The value was related to the affinity of the alloying elements with nitrogen.
(3) The composition of the compound layers formed on the surface of nitrided was affected mainly by the kind of the alloying elements, but in pure iron and Mn-bearing alloys, it is also affected strongly by the gas composition of the nitriding atmosphere.View full abstractDownload PDF (1056K) -
Hideo Tezuka, Fusao Hayama1976 Volume 40 Issue 7 Pages 669-672
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSYoung’s moduli of oxides scale of steel at elevated temperatures were measured by the method of longitudinal vibration. The values obtained in our experiment agreed well with the results of Bruce who had used the method of transverse vibration. The frequency change due to oxidation in the transverse vibration method was less stable than that of the longitudinal one, and consequently more stable results were easily obtained by this method. The Young’s moduli of the oxides scale of ferrite spheroidal graphite iron showed values about 20% smaller than those of steel. The reason for this can be considered as due to the existence of an appreciable amount of complex oxides, FeO·SiO2, in the oxides scale.View full abstractDownload PDF (306K) -
Toru Miyazaki, Hiroshi Murayama, Hirotaro Mori1976 Volume 40 Issue 7 Pages 673-681
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStructural changes of Ni-Cu-Si alloys during aging were investigated by means of transmission electron microscopy and X-ray analysis. The results obtained are as follows:
(1) In an early stage of aging, periodic phase decomposition was observed along the [100] direction, and its spacings did not change for a certain time. This stage can be explained by Cahn’s spinodal theory. Critical temperatures of spinodal decomposition increase with Si content. (2) In the case of aging with a large driving force of spinodal decomposition, coherent γ′ particles are created in each zone formed by the spinodal decomposition and the particles increase in size and spacing keeping an excellent periodicity and alighnment along [100] and [110] directions. As the aging temperature is farther from spinodal, the m values which show the relationship between spacing (Q) and aging time (t), (Q∝tm), become smaller. (3) In the case of lower Si content or high temperature aging, γ′ particles are precipitated in the “tweed structure” which has been formed after the [100] phase decomposition. The γ′ particles are thought to be created through two kinds of mechanisms, that is, coherent and incoherent nucleations. The coherently created γ′ particles are arranged periodically to [100] and [110] directions, while in the later case γ′ are in random distribution. X-ray side bands can be observed in the alloys aged under conditions of coherent γ′ formation.View full abstractDownload PDF (1221K) -
Masakatsu Hinai1976 Volume 40 Issue 7 Pages 682-686
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSElectrical resistivity ρ, crystal magnetic anisotropy constant K1, saturation magnetostriction constant λs and the ΔE effect have been measured to investigate the cause of high permeability in the Ni-Fe-Nb system.
The values for ρ of Ni-Fe-Nb alloys augment with decreasing cooling rate and diminishes with increasing reduction in area by cold working; the change in ρ becomes more pronounced with increasing Nb content. These results prove that the K-state grows in these alloys. The absolute values of K1 and λs, and the value of ΔE⁄E0 decrease by addition of Nb to Ni-Fe alloys, becoming very small near the composition which shows the highest initial permeability.
From these results, it may be concluded that the high permeability of Ni-Fe-Nb alloys is caused by the very small values of K1, λs and the ΔE effect.View full abstractDownload PDF (362K) -
Hakaru Masumoto, Masakatsu Hinai, Y\={u}etsu Murakami1976 Volume 40 Issue 7 Pages 686-690
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNi-Fe-Ta-W alloys were heated in hydrogen atmosphere at 1150°C for 3 hr and then cooled at various rates from a temperature above their order-disorder transformation points. The highest initial permeability of 101000 is obtained with the alloy of 73.40%Ni, 10.96%Fe, 14.11%Ta and 1.53%W cooled at the rate of 200°C/hr, and the highest maximum permeability of 557000 with the alloy of 73.50%Ni, 10.96%Fe, 14.99%Ta and 0.55%W cooled at 300°C/hr. The alloy having the highest initial permeability exhibited the electrical resistivity of 71.4 μΩ-cm, with 210 Vickers hardness. The high permeability of the Ni-Fe-Ta-W alloys is largely due to the effective contributions of the high-temperature heat treatment in hydrogen atmosphere to the homogeneity of alloys and removal of impurities, associated with the low values of saturation magnetostriction and crystal magnetic anisotropy in a proper state of ordering.View full abstractDownload PDF (373K) -
Fusao Togashi, Taiji Nishizawa1976 Volume 40 Issue 7 Pages 691-700
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe growth rate and the interlameller spacing of pearlite were determined for molybdenum steels, and the mechanism of the growth process was studied from a phenomenological point of view. The growth rate equation was obtained by an extention of the theory proposed by Machlin (1953) and was quantitatively examined taking into consideration of the mobility of the austenite/pearlite (or ferrite) interface, which had been evaluated in the preceding work. It was recognized that the pearlite growth is not a simple diffusion-limited process but combined processes of diffusion and interface migration. The mode of diffusion of carbon atoms was estimated to be an interface diffusion along the austenite/pearlite interface. The interface migration was ascertained to be a predominant process in the pearlite growth of molybdenum steels, where molybdenum atoms might segregate to the austenite/pearlite interface and reduce its mobility as is often the case with the grain boundary migration.View full abstractDownload PDF (886K) -
Ry\={u}ta Onodera1976 Volume 40 Issue 7 Pages 701-708
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEstimation of fracture strain of ductile round bar specimen, having a given initial volume fraction of voids, was tried using the previously reported equation for the ductile fracture condition. As the equation involves four variables i.e. volume fraction of voids, v, relative radial stress, σr⁄Y, relative work hardening ratio, \dfracdσ⁄dεσ, and specimen size, changes of these variables with strain were investigated.
σr⁄Y at the center of the neck of specimens was expressed in terms of the curvature radius of the neck, R, and a radius of the section of specimen, r, using Bridgman’s equation. It was shown that r⁄R could be uniquely related to strain, ε, irrespective of examined materials. Next, densities of the necked region of tensile specimens of several materials (low carbon steel, stainless steel, aluminium, etc.) were measured. Using these results, experimental equations for the change in volume fraction of voids with the effect of work hardening and the difference in materials were obtained. Applying these equations, the v-ε curve of a specimen having a given volume fraction, v0, could be drawn.
Using r⁄R-ε, and v-ε curves and the equation for the fracture condition, the relation between fracture strain εf and initial volume fraction of voids v0 could be obtained graphically in each case of three different n-values \left(σ=Cεn,\dfracdσ⁄dεσ=\dfracnε\ ight) and three different specimen sizes, which agreed well with the experimental results (Edelson, et al., present work). The theoretical expectation that fracture strain increases with n-value and decreases with specimen size, agreed quantitatively with the experimental results described in this paper.View full abstractDownload PDF (644K) -
Motomichi Doi, Taisaku Sato, Fusao Hayama1976 Volume 40 Issue 7 Pages 709-715
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTo investigate fundamentally the influence of water on the wear mechanism, brass, bronze and 18-8 stainless steel were slid against chromium plated steel in pure water, and the results were discussed comparing with those in air. Further experiments on 60/40 brass were made in white spindle oil, in solutions of hydrogen peroxide and in a solution of hydroquinone, in order to investigate the effects of water on wear.
The results are obtained as follows:
(1) In pure water the wear rate of each material decreases by a factor of 10∼20 and the coefficient of friction does by a factor of 2∼4 as compared with those in air. (2) Both brass and bronze are oxidized during sliding and then their wear rates decrease in air, while in pure water the worn surfaces are almost metallic and sometimes locally oxidized, nevertheless the wear rate is low. (3) In white spindle oil 60/40 brass shows the wear rate larger than in pure water. This suggests that there are some factors aiding the lubricating action of water. (4) In a somewhat reductive solution of hydroquinone and in an oxidative solution of hydrogen peroxide the specific wear of 60/40 brass is more pronounced than in pure water. This is probably due to the fact that the sliding surface in water is covered with an oxide film of moderate thickness. (5) In pure water the adhesion of the surface becomes moderate by oxidizing, cooling and lubricating, so that the surface of brass is easy to flow and becomes smooth. This smoothness causes the sufficient lubricating action of water.View full abstractDownload PDF (1200K) -
Shigeatsu Nakazawa, Akira Yazawa1976 Volume 40 Issue 7 Pages 715-722
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSConsiderations are given to the determination of thermodynamic activities of liquid solutions, where the equilibrium vapor pressures of components are close to each other, by the “two-components evaporation method”. In this method, the activity coefficient, γA, in the A-B system is evaluated employing the relative volatility:
(This article is not displayable. Please see full text pdf.)
\ oindentThe experimental technique consists of the analysis of the equilibrium vapor which effuses into a vacuum through an orifice, or is transferred by the carrier gas.
In order to test the feasibility of the method, experiments were carried out on the liquid Pb-Tl alloy at 853 K (the effusion technique) and on the fused CdCl2-PbCl2 salt at 963 K (the transpiration technique).
The results can be represented over the whole range of composition by the equations
(This article is not displayable. Please see full text pdf.)
\ oindentfor the Pb-Tl system at 853 K and
(This article is not displayable. Please see full text pdf.)
\ oindentfor the CdCl2-PbCl2 system at 963 K. The soundness of these results was checked on the figure using the literature data on vapor pressures of pure components.
A new method of deriving the activities is also presented in which the changes of the absolute amounts of components are successively pursued, and the sample composition is shifted in contrast with the usual method.View full abstractDownload PDF (679K) -
Hideo Tai, Shigenori Hori1976 Volume 40 Issue 7 Pages 722-725
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe equilibrium phase diagrams of the CdTe-CdCl2 and CdTe-CdBr2 systems have been determined by means of X-ray diffraction, differential thermal analysis and dissolution measurement.
These two systems can be considered as pseudobinary systems from the results of X-ray diffraction. The phase diagrams are a simple eutectic type. The eutectic point is determined to be 505°C, 74 mol%CdCl2 for the CdTe-CdCl2 system and 513°C, 73 mol%CdBr2 for the CdTe-CdBr2 system. The mutual solid solubilities of these systems cannot be detected by X-ray analysis.View full abstractDownload PDF (311K) -
Hisashi Suzuki, Teruyoshi Tanase1976 Volume 40 Issue 7 Pages 726-732
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe transverse-rupture strength of WC-Co cemented carbide was studied at room temperature in relation to carbide grain-size and binder content, and analyses of the strength were carried out on the basis of our previous work which demonstrated that the strength is directly controlled by the existence of microstructural defects. The rupture strength was analyzed as a function of dimensions and location of the defect observed on the fracture surface. The following equation was assumed for the strength analysis: σd(1+2\sqrta⁄ρ)=σ0, where σd is the external stress which acted on the defect at the moment of fracture, a is one half of the defect size, ρ is the effective radius of curvature at the end of the longitudinal axis of the defect, σ0 is the strength of the sound matrix free from defects.
Results obtained were as follows. (1) The transverse-rupture strength reached a maximum at certain mean grain size (binder content) when the binder content (mean grain size) was kept constant. However, both values of the structural parameters giving a maximum strength were smaller than those reported by previous reseachers. This was thought to be due to the fact that the strength is governed by the defect characteristic of the specimen. (2) Thus, it was noted that both values of the structural parameters as well as the strength of the alloy have to be discussed in terms of σ0, ρ, a, etc. The σ0 vs. λ (mean free path of binder phase) and the ρ vs. λ plots were shown by a single curve, respectively, regardless of the grain size and the binder content. The peak of the σ0 vs. λ plot, about 850 kg/mm2 in height, was located at λ\simeq0.15 μ. (3) Further study about the nature of σ0 and ρ obtained seems to be needed, since the influence of carbide contiguity or plastic deformation should be taken into account in the evaluation of the above values.View full abstractDownload PDF (727K) -
Hisashi Suzuki, Kozi Hayashi, Yasuro Taniguchi1976 Volume 40 Issue 7 Pages 732-738
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe transverse-rupture strength of WC-10%Co cemented carbide was studied in the temperature range from room temperature to 900°C, paying attention to the structural defects or some defects which would act as a fracture source. The WC-10%Co alloy of medium carbon content with a mean carbide grain-size of about 1.2 μ was vacuum-sintered and used as specimens. The transverse-rupture strength test was carried out according to the Japanese Industrial Standard.
The results obtained were as follows: (1) Below about 600°C, common structural defects such as pores or coarse WC grains were confirmed to act as fracture sources; however, at higher temperatures above about 600∼700°C, they did not tend to act as fracture sources. At still higher temperatures, a small region with irregularly rugged appearance, i.e., a region of stable crack propagation, was formed due to increased plasticity of the alloy. It was found that the region did not act as a fracture source. (2) The strength of the sound matrix having none of the defects gradually decreased with rising temperatures up to about 600°C; it sharply did above about 600∼700°C and above about 800°C it agreed with the transverse-rupture strength of the alloy. (3) The sharp changes at about 600∼700°C in the fracture mode which are closely related to the change in the sort of fracture source and strength of the alloy, etc., would be related to the strain-induced transformation of the binder phase.View full abstractDownload PDF (812K) -
Masuo Hagiwara, Tomoo Suzuki1976 Volume 40 Issue 7 Pages 738-743
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to estimate the thermodynamic interaction parameter Ω for the bcc phase of the binary system, the effect of the addition of a third element (Cr, Mn, V) on the order-disorder transition temperature (Tc) of the CsCl-type FeCo superlattice has been investigated by means of differential thermal analysis. Also the effect of Co addition on the miscibility gap in the Fe-Cr system has been investigated.
The Tc of the FeCo superlattice is lowered by the addition of Cr or V and raised by the addition of Mn. The critical temperature of the miscibility gap in the Fe-Cr system is raised by the addition of Co. From these experimental results, the following values of the parameters have been obtained:
(This article is not displayable. Please see full text pdf.)
\ oindentBased on these parameters, some aging and transformation behaviors of Fe-Co-Cr, Fe-Co-Mn and Fe-Co-V alloys have been discussed.View full abstractDownload PDF (532K) -
The Effect of Small Repeating Stress on the Delayed Fracture Crack Initiation in High Strength SteelKeijiro Nakasa, Mitsuo Kido, Hideo Takei1976 Volume 40 Issue 7 Pages 744-751
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influence of superposition of small repeating stress on the crack initiation time in delayed fracture was investigated using the notched specimen of the high strength Ni-Cr-Mo steel. The results obtained are as follows:
(1) The crack initiation time in delayed fracture is decreased to greater extent by the superposition of small repeating stress as the stress amplitude or the repeating frequency is increased.
(2) The lower limit stress under which no delayed fracture occurs is markedly decreased by the superposition of small repeating stress.
(3) The reason why the crack initiation life in delayed fracture is decreased by such a superposition of small repeating stress, can be explained by both the change of sensitivity against delayed fracture in the material near the notch tip during repeating stress and the promotion of corrosion reaction caused by, for example, the destruction of oxide film.View full abstractDownload PDF (791K) -
Nobumasa Kemori, Iwao Katayama, Zensaku Kozuka1976 Volume 40 Issue 7 Pages 751-757
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe e.m.f. measurements of a galvanic cell with the solid electrolyte were carried out in order to determine the activities of oxygen in liquid nickel at two temperatures of 1460 and 1510°C. The cell used was as follows:
(This article is not displayable. Please see full text pdf.)
\ oindentFrom these experimental results, it was found that:
(1) Activity of oxygen in liquid nickel was found to obey Henry’s Law at both temperatures up to such a high oxygen content that NiO precipitated, and the activity coefficients of oxygen were 0.229 at 1460°C and 0.252 at 1510°C, respectively. The relationships between e.m.f. of the cell described above and oxygen content were expressed as follows:
(This article is not displayable. Please see full text pdf.)
(2) Solubility of oxygen in liquid nickel was given by the expression
(This article is not displayable. Please see full text pdf.)
(3) The standard free energy change for the reaction 1⁄2 O2=O (in liquid Ni) was shown by
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (565K) -
Toshihiro Yamada1976 Volume 40 Issue 7 Pages 757-763
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe frictional Hardened layers which occurred in the sliding as well as in the cutting and grinding surfaces under a severe condition would be classified into two different types by microscopic observation: black colored one which can be recognized without etching, and the white one which is stable with nital or picral etching.
In this study, the mechanism of the formation and some properties of the white hardened layers induced in the sliding surface of the annealed carbon steels were examined in the case of a similar metal contact under the lubricated condition.
The experiments were carried out using a Pin-and-Disk type wear machine at a constant sliding speed and load (4.0 m/sec and 40 kg).
The specimens were prepared from 0.20%, 0.40%, 0.58% and 0.90%C steels containing nearly equal amounts of silicon and manganese.
It was found that the white hardened layer was very hard (Hv(50 g)=1100) and exhibited a compressive stress of about 60 kg/mm2. But the value of compressive stress and the maximum hardness of this hardened layer did not vary with the carbon content of the specimens.
Many carbides were observed in the hardened layer when etched with alkaline sodium picrate, and X-ray microanalysis showed only the presence of carbon in the hardened layer.
On the other hand, it was found by X-ray diffraction that the hardened layer consists of α-Fe, α′-Fe, γ-Fe and Fe3C, and that the amount of retained austenite does not vary with the carbon content of the specimens.
It was considered that the source of the carbon contained in large quantities in the hardened layer was the lubricant.
Accordingly, it was concluded that the white hardened layer was the result of rapid solidification of the melting regions onto the real contacting zone.View full abstractDownload PDF (1008K)
- |<
- <
- 1
- >
- >|