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Volume 43, Issue 3
Displaying 1-19 of 19 articles from this issue
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Kumayasu Yoshii, Takashi Tsukamoto, Masataka Umeno, Hideaki Kawabe1979 Volume 43 Issue 3 Pages 155-161
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to develop the composite materials with very high strength and without brittle fracture, as suggested by Koehler, Cu/(001)Ni double layer films were made epitaxially in a vacuum system at a pressure of less than 6.7×10−6 Pa. Interfacial structures of double layer films were investigated by the transmission electron microscope, and the influence of interfacial structures on the strength of double layer films was also discussed.
\ oindentThe results are as follows:
(1) The epitaxial growth of Cu films on (001)Ni substrates was a monolayer overgrowth type at the substrate temperatures of 80 and 160°C, and an island growth type at 260 and 350°C.
(2) Cu/(001)Ni double layer films, which were prepared by monolayer overgrowth of Cu films on(001)Ni at the temperature of 160°C, were examined by the transmission electron microscope. The results showed that moiré fringes were observed all over the films, and that as the thickness of Cu films increased, moiré fringe spacings decreased, and finally that misfit dislocations were lying in the deposit-substrate interface. Therefore, it was clarified that misfit between Cu deposit and Ni substrate lattices was accomodated by introduction of misfit dislocations.
(3) Spacings of misfit dislocations in Cu films of various thicknesses were 9.3 nm in average and the direction of dislocation lines was ⟨110⟩, and the Burgers vectors were of the edge type lying in the deposit-substrate interface.
(4) Resolved shear stresses of the Cu/(001)Ni double layer films, which were calculated from the repulsive force due to the stress field of misfit dislocation arrays against the glide dislocations in the Cu film, were zero in the case of screw dislocations parallel to misfit dislocations, but of the order of 109 Pa in the cases of other dislocations. Thus it is necessary to consider the contribution of misfit dislocations to the strengthening of double layer films.View full abstractDownload PDF (755K) -
Yoshinari Kaieda, Atsushi Oguchi1979 Volume 43 Issue 3 Pages 161-169
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to clarify the effect of high hydrostatic pressure on the brittle fracture stress, three point bending tests have been carried out for an Fe-Cr alloy (σ-phase) containing about 47%Cr and 0.7%Si at atmospheric pressure and under 800 MPa at temperatures up to 1200 K. In the temperature range from room temperature to 1140 K, the specimens remained in the σ-phase and transgranular cleavage fracture occurred under both pressures. By scanning electron microscopy, the fracture surface consisted of river patterns and Wallner lines. The fracture stress at atmospheric pressure increased gradually with increasing temperature to about 1000 K and increased rapidly at higher temperatures. The same tendency was observed in the tests under 800 MPa but the tracture stress under 800 MPa was always higher than that at atmospheric pressure, and the difference between these stresses became larger at higher temperatures than about 1000 K. From a consideration of the stress condition around a crack, a formula σFP=σF0+P⁄Kσ was proposed to represent the influence of hydrostatic pressure on the brittle fracture stress at low temperatures, where σF0, σFP are the fracture stresses at atmospheric pressure and under high pressure, P is the pressure in positive sign and Kσ is the stress concentration factor at the crack. At higher temperatures, Kσ was replaced by Neuber’s plastic stress concentration factor Kσ*.View full abstractDownload PDF (1074K) -
Mikio Fukuhara, Hiroyasu Mitani1979 Volume 43 Issue 3 Pages 169-174
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to investigate the phase relationship during the sintering process of TiN-Ni mixed powder compacts, the nickel-rich portion of the vertical section between nickel-solid solution and titanium nitride was studied by using both sintered and arc-melted alloy specimens prepared from Ni and TiN, where a quasi-binary eutectic was found between a nickel-solid solution and stoichiometric TiN in the vertical plane. The eutectic composition was determined to be about 10 wt%Ti and 1.6 wt%N, and the melting point of the eutectic was found to be 1353±4°C. The maximum solubilities of Ti and N in the nickel-solid solution and the nickel solubility in the TiN phase at 1353°C were obtained as 4.84 wt%Ti, 0.06 wt%N and 0.31 wt%Ni, respectively.
The structure of a quasi-binary eutectic between nickel-solid solution and TiN showed a complex stripe-like structure.
It was found that nitrogen gas liberated with formation of nickel-solid solution, but not from the liquid phase during the sintering process of TiN-Ni mixed powder compacts. Judging from the sintered densities, the liquid phase sintering of TiN-Ni mixed powder compacts may be disturbed by liberated nitrogen gas which increase from about 800°C to the eutecic temperature.View full abstractDownload PDF (528K) -
Katsuro Kuroki, Takashi Sato, Toshiya Wada1979 Volume 43 Issue 3 Pages 175-181
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInhibitors for developing grain oriented silicon steel have been studied. Four specimens A, B, C and D were prepared. A was fairly free from any minute elements or impurities, B was doped with MnS and was suitable in composition for ordinary grain oriented silicon steel produced by the two stage cold rolling process, C was doped with MnS and AlN and D was doped with MnSe and Sb. Specimens C and D were suitable for high degree oriented (110)[001] textured steel. Primary recrystallized specimens ware annealed at constant temperature, and the relationship between the rate of grain growth and the morphology of dispersed particles was examined.
The main results obtained were as follows:
\ oindentSpecimens C and D showed the lowest grain growth rate of 10−8∼10−9 cm/s at 900°C, followed by specimens B and A in increasing order. The average size of the precipitates was 1.3∼1.4×10−6 cm for C, 1.8×10−6 cm for B, and 2.15×10−6 cm for A. The number of precipitates per unit volume was 1.9∼2.1×1014/cm3 for C and D, 5.9×1013/cm3 for B, and 2.7×1013/cm3 for A.
It is concluded that in order to induce a high degree oriented (110)[001] secondary texture, the disperesed precipitates require a strong inhibiting power than in the case of ordinary grain oriented silicon steel.View full abstractDownload PDF (1507K) -
Masahiro Sakai, Osamu Watanabe, Katsuya Watanabe1979 Volume 43 Issue 3 Pages 181-189
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarbon fiber-reinforced copper composites were prepared by two methods, one was by an electrodeposition and the other was by a hot-pressing after the electrodeposition. The tensile strength of the composites along the fiber direction was measured. For the composites obtained by electrodeposition, the reinforcement of the matrix due to the internal stress induced by the electrodeposition was superimposed on the reinforcement by the fibers. While the strength of the composites prepared by the latter method depended remarkably on the hot-pressing condition. The structural observation showed that the matrix of the composites having lower strength was porous. Since the surface of the electrodeposited copper was relatively rough, it could be assumed that pores which were liable to spread perpendicularly to the fiber direction were formed and this shape of pore would be responsible for lowering of the tensile strength of the composites.View full abstractDownload PDF (1399K) -
Yoshiichi Sakamoto, Kazunori Nagatani1979 Volume 43 Issue 3 Pages 190-194
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn investigation of the effect of aged structures on diffusivity and solubility of hydrogen in a commercial 18Ni maraging steel has been carried out at room temperature by the electrochemical permeation technique.
The diffusion coefficient and solubility of hydrogen vary with the aged structures of the steel. When the steel is aged at 400 to 450°C for 1 to 3 h, the former shows a minimum, while the latter exhibits a maximum. These variations in diffusivity and solubility of hydrogen can be interpreted in terms of the difference between hydrogen trapping effects of various lattice imperfections, such as dislocations and their stress fields, together with the interfaces between the precipitates and the matrix of martensites introduced by the formation of zones and/or by the precipitation of metastable phases during aging. The solubility of hydrogen is high and the diffusion coefficient is low in the structures aged at higher temperatures for long times. This corresponds to the overaging structure caused by the combination of usual overaging and the formation of nickel rich-austenites in the structure. Thus, the diffusion coefficient in the austenitic structure formed by the reversion of martensites during aging seems to be lower than that in the martensitic structure caused by solution treatment.View full abstractDownload PDF (665K) -
Yasushi Shimanuki1979 Volume 43 Issue 3 Pages 195-203
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSApplication of existing theories of age-hardening due to ordered phase to the measured strength of Udimet 520 has revealed that the theoretical predictions of particle spacing along a dislocation are lacking in validity and should be elaborated. In this study, distribution of γ′ particles in a slip plane in Udimet 520 was determined on the basis of direct observations of partial dislocation loops formed around particles during creep deformation. Then the sequence of dislocation movement through the array of γ′ particles was examined. The mean particle spacing along a dislocation was determined and expressed as a function of the size and volume fraction of particles and the applied stress. A comparison of the values of particle spacing evaluated in this study with existing theoretical predictions was made.View full abstractDownload PDF (860K) -
Yasushi Shimanuki1979 Volume 43 Issue 3 Pages 203-208
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNew expressions of precipitation hardening due to a coherent, spherical, ordered phase were developed on the basis of a realistic evaluation of the particle spacing along a dislocation in Udimet 520. Such expressions had a clear difference from existing theories based on the theoretical predictions of particle spacing. Age-hardening in Udimet 520 and several Ni-Al alloys was revealed to be in excellent quantitative agreement with the new expressions.View full abstractDownload PDF (495K) -
Hiroshi Yamagata, Osamu Izumi1979 Volume 43 Issue 3 Pages 209-216
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOn the ductility of α solid solution alloys, such as Cu-Al, Cu-Zn, Cu-20%Ni and Cu-2%Si, the effects of compositions and strain rates were examined over a wide range of temperature. The results are summarized as follows:
(1) The ductility in the low temperature range of about 77∼500 K, was related to the work hardening characteristic that depends on the stacking fault energy.
(2) The intermediate temperature embrittlement was observed in all alloys excepting the Cu-Ni system, and it became more pronounced with increasing solute concentration.
(3) In the higher temperature range above 800 K, the ductility increased abnormally, and the behaviour was explained by the solute dragging motion of dislocations.
(4) The above change in ductility appears to be commonly observed in many other α solid solutions of copper alloys.View full abstractDownload PDF (684K) -
Hidehiko Kamide, Hideo Sugawara1979 Volume 43 Issue 3 Pages 216-222
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInfluences of applied stress on stress corrosion cracking (SCC) and those of annealing on the corrosion morphology of α′-martensite were investigated in order to clarify the role of stress in the mechanism of SCC of 18-8 stainless steel in H2SO4-NaCl solution.
The fracture time of specimens by SCC was decreased with increasing the degree of prestraining and applied stress. Compared with a prestrained specimen, the fracture time of a solution treated specimen was dependent strongly on the level of applied stress. The deep corrosion striations were observed on a prestrained specimen without applied stress and also on the compression site of the U-bend specimen after immersion in the solution. The SCC behavior of the steel in the solution was thought to be closely related with the preferential dissolution of martensite in the austenitic matrix.
Wide corrosion grooves were found for a subzero treated specimen in the immersion test as the result of preferential dissoluiton of the α′-martensite. The harf-value width of α′-martensite peaks in X-ray diffraction patterns of subzero treated specimens decreased with increasing annealing time at 673 and 773 K. By the annealing at 673 K for 300 h prior to the immersion test, the needle-shaped protuberances remained on the side wall of the corrosion grooves. This corrosion morphology was the same as that of annealing at 1283 K for 0.5 min when the α′-martensite disappeared. These results suggest that the dissolution of α′-martensite may be related to the presence of a large number of lattice defects in it.
A prominent role of applied stress in SCC is thought to form the strain induced martensite containing a large number of lattice defects in the austenitic matrix of the steel, enhancing the SCC susceptibility.View full abstractDownload PDF (1024K) -
Etsuji Kimura, Seitaro Fukushima1979 Volume 43 Issue 3 Pages 223-229
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis paper describes the vapor-liquid equilibria of Cl2 and CO2 to separate CO2 from liquid chlorine. The vapor-liquid equilibria were measured with a 300 ml autoclave made of glass, which was set up in a constant temperature freezer, under the temperature range from 16 to −50°C and the pressure range from 1 to 10 atm. There were six steps in the experimental operations : charging gaseous pure chlorine, liquifying it, dissolving carbon dioxide, equilibration in the desired conditions, sampling the equilibrium vapor and liquid, and sample analysis. The composition of vapor and liquid was determined by gas-chromatographic analysis.
The results were analyzed thermodynamically and compared with the calculated lines of the ideal solution, the regular solution and the modified regular solution. The calculated results for these solutions were in fairly good agreement with the experimental data in the gas phase, but in the liquid phase, considerable deviations from the experimental data were observed in each model. To explain the deviations, the interaction parameter (mL) between Cl2 and CO2 was introduced to the modified regular solution model. The value, mL=0.94, was in close agreement with the data and was almost independent of temperature beyond −20°C, while the value of mL decreased to 0.93 at −30°C and 0.925 at −40°C.View full abstractDownload PDF (490K) -
Kazuyoshi Takezawa, Kenji Adachi, Shin’ichi Sato1979 Volume 43 Issue 3 Pages 229-235
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe reversible shape memory effect (RSM) was found to appear in Cu-Zn-AI alloys after a heat-treatment under constraint without severe deformation. A series of detailed investigations have been performed to understand this phenomenon. This paper represents the results of mechanical test associated with the RSM as well as those of the corresponding metallographic examinations.
Three stages of stress variation were observed with respect to temperature in tensile tests under a fixed elongation of polycrystalline specimens. In the first stage the stress increases with temperature where the reverse transformation (β′1→β1) of stress-induced martensites (SIMs, β′1) occurs. The second one with a lower increasing rate follows at temperatures greater than about 60°C, the decrease in rate being caused by the yielding of SIMs. The last one at temperatures higher than 180°C shows a decrease in stress with temperature, where the bainitic transformation takes place.
The RSM was produced by heating the specimen under constraint only at the temperatures corresponding to the second stage in the above test, i.e., about 60∼180°C. The metallographic examinations reveals that the yielding stabilizes the β′1 SIMs, and also that the RSM is predominant in the grains where a large amount of the stabilized SIMs remains to form complex structures in the matrix. The result that the stabilized β′1 has a different crystal structure from 9R, i.e., 3R called α′1, will be described in the next paper.View full abstractDownload PDF (919K) -
Kazuyoshi Takezawa, Hiroyasu Sato, Yoshitaka Abe, Shin’ichi Sato1979 Volume 43 Issue 3 Pages 235-241
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe reversible shape memory effect (RSM) has been obtained by severe deformation or by heating under constraint in some Cu-base martensitic alloys. The previous investigations of Cu-Zn-Al alloys on the mechanical properties and metallography suggested that the two step stress-induced transformation β1→β′1→α′1, occurred, and also that the second martensite α′1 played an important role in producing the RSM. In this study, to recognize this kind of transformation and to understand the shape change in relation to the transformation shears, detailed crystallographic examinations were made with large-grained specimens by mainly using X-ray Pseudo-Kossel method. The results are summarized as follows:
(1) The structure of α′1 martensite is fct (3R) which is produced by simple shear on the basal plane in β′1 martensites (9R).
(2) In the course of reverse transformation on unloading or on tempering under constraint, complex structures consisting of α′1 and β′1, called “X”, are produced by the α′1→β′1 transformation accompanying the β′1→β1 transformation.
(3) The structure “X” produces a special stress field around which the formation of β′1 martensites with the same variant as the initial one is induced. This transformation is followed by the shape change with temperature, i.e., the RSM.View full abstractDownload PDF (1331K) -
Lattice Hardening and Anomalous Softening of Iron and Steel Caused by Electrolytic Hydrogen ChargingShigeru Asano, Yoichi Nishino, Rikuro Otsuka1979 Volume 43 Issue 3 Pages 241-248
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to clarify the intrinsic effect of dissolved hydrogen on the mechanical properties of iron and steel, the results obtained in a tensile experiment were critically examined with special attention to some subsidiary effects caused by the electrolytic method of hydrogen charging. The experimental analysis leads to the following conclusion: (1) The electrolytic method of hydrogen charging inevitably produced an unexpected deterioration in the surface layer of a specimen, together with the introduction of dissolved hydrogen in iron and steel. This was confirmed in a tensile experiment by the effect of specimen size on the change in flow stress caused by electrolytic hydrogen charging. (2) The introduction of dissolved hydrogen always raised the flow stress of iron and steel, showing hydrogen-induced lattice hardening. This should be considered as an intrinsic change in bulk property of materials, because it was independent of specimen size for larger specimens. (3) Some purer materials showed an anomalous softening caused by electrolytic hydrogen charging, which occurred only in the case of very small sizes of tensile specimens. Such a softening seemed to originate in a surface damage due to hydrogen precipitation.View full abstractDownload PDF (711K) -
Toshihei Misawa, Hideo Sugawara, Tetsuo Shoji, Tadashi Harada1979 Volume 43 Issue 3 Pages 249-257
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study has been made of fatigue crack growth in Inconel 600 and Incoloy 800 in a pure water environment containing 15 ppm dissolved oxygen at 85°C at a frequency of 1 cpm. The effects of solution-annealed and sensitized heat treatments and nickel content on the corrosion fatigue crack growth rates as a function of ΔK were examined and the fracture surfaces were observed. The results obtained are as follows:
(1) The fatigue crack growth rates of Inconel 600 in pure water were greater than that of solution-annealed Inconel 600 in a reference air environment. This crack growth acceleration in oxygenated water can be explained by assuming, on the basis of fractographic observation of fatigue fracture surfaces, that an active dissolution on the fresh metal-surfaces nucleated with the crack tip plastic deformation will result in the formation of larger fatigue striation spacing and the increased crack propagation.
(2) In both Inconel 600 and Incoloy 800, the heat treatment for 24 h at a sensitizing temperature of 650°C led to a reduced corrosion fatigue crack growth rate compared with that in those alloys solution-annealed. This result obtained for the high-nickel alloys shows a reversal of the sensitizing effect on the crack growth rate in Type 304 stainless steel.
(3) The fatigue crack growth rate of austenitic Ni-Cr-Fe alloys in pure water decreases with an increase in nickel content, namely Type 304 stainless steel, Incoloy 800 and Inconel 600 at a certain ΔK.
(4) The corrosion fatigue fracture surfaces of high-nickel alloys grown in the pure water environment at 85°C show a fracture mode of fatigue striations.View full abstractDownload PDF (1521K) -
Hideo Onoue, Takashi Sakaki, Kazutaka Sakiyama1979 Volume 43 Issue 3 Pages 258-262
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCorrosion tests on mild steel, cast iron and pure iron were performed in 48% caustic soda solutions containing varying amounts of NaClO3 and NaCl at temperatures between 100 and 200°C. The results obtained are summarized as follows.
(1) As the potential increased the anodic iron dissolve as FeO22−, FeO2− and FeO42− ions. Dissolution of FeO2− ion and the second passivity change remarkably by the sweep rate of potential. (2) The logarithms of the average penetration and temperature show a linear relationship. (3) But the corrosion rates of cast iron and mild steel decrease in order to form the protective passivation film, Fe3O4, at certain temperatures. (4) The corrosion rate is affected when NaClO3 is contained in caustic soda solutions. (5) It is found that the corrosion of iron is unchangealble in 48%NaOH solutions containing NaCl that is 1% or less.View full abstractDownload PDF (381K) -
Yasumasa Koyama, Osamu Nittono1979 Volume 43 Issue 3 Pages 262-270
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe structural change and the shape memory behavior in indium rich-(0∼6.20 at%) cadmium alloy crystals have been studied at both normal and elevated temperatures using X-ray and electron diffraction methods supplemented by optical microscopy. Polycrystals as well as single crystals are used as specimens. At 25±1°C the tetragonal phase changes to cubic at 5.6 at%Cd, and no metastable two-phase region is defined. Etched surfaces of tetragonal alloys show a banded structure parallel to {101} planes, as in the analogous indium-thallium alloys. On heating the alloys transform fct to fcc, and the fct\ ightleftarrowsfcc transformation is of the diffusionless type. Single crystals transform by the migration of a single interface, although the mobility is influenced by the history of mechanical deformation assigned to the specimen. In-(4.0∼5.5 at%)Cd alloys have a shape memory effect, but In-Cd alloys with more than 5.6 at%Cd does not show any shape recovery. X-ray topographic observations on heating show that the shape recovery is related with the migration of twin boundaries and also with the annihilation of the twinned structure. The shape memory effects in both In-Tl and In-Cd alloys are presented and compared with one another. Strong non-radial diffuse streak patterns are observed in X-ray and electron diffraction experiments. They are not streaks from elastic strain, but they are ascribed to thermal diffuse streaks which are related with lattice vibrations with low frequencies. The lattice stability and the microscopic nature of atom movements are discussed on the basis of lattice vibration.View full abstractDownload PDF (1085K) -
Toshio Shibata, Taro Takeyama1979 Volume 43 Issue 3 Pages 270-278
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPit generation of Incoloy 800 in 3.5%NaCl solution has been analysed on the basis of a stochastic theory. A parallel combination of several processes was found to be included in the pit generation at a constant potential. The number of the processes and their pit generation rates altered depending on the pretreatment potential as well as the potential applied during pit generation. The increase of the pretreatment potential caused to decrease the number of the process and also the rate of pit generation. The critical pitting potential which does not depend on the pretreatment potential and the potential sweep velocity can be determined when the pretreatment potential is more noble than −0.10 V.View full abstractDownload PDF (644K) -
Yoichi Kimura1979 Volume 43 Issue 3 Pages 279-280
Published: 1979
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (129K)
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