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Volume 38, Issue 9
Displaying 1-16 of 16 articles from this issue
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Yukio Nishiyama, Takao Uemura, Kiyoshi Kita, Tadashi Hayashi, Takashi ...1974 Volume 38 Issue 9 Pages 779-787
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh cycle fatigue testing has been conducted on wrought Ni-base superalloys M 252, Waspaloy, U 500 and U 700, which are widely used as turbine blade materials for jet engine and gas turbines. The results obtained are as follows.
(1) At short lives up to 106 cycles, all alloys are the strongest at room temperature, whereas at long lives near 107 cycles, M 252, Waspaloy and U 500, U 700 are the strongest at about 600 and 800°C respectively.
(2) The fractures show a cleavage like feature over a comparatively large range from the initiating site.
(3) From the results of some experimental work, the following conclusions were obtained in regard to such an unusual temperature dependence and fractured surfaces:
(i)\phantomii When the strain rate of flow stress is made to approach that of fatigue testing, the peak temperature of flow stress coincides with that of high cycle fatigue testing in each alloy and the peak temperature is determined primarily by the volume faction of γ′.
(ii)\phantomi During high temperature fatigue testing of U 700, dislocation networks surrounding γ′ are formed partially, which are similar to dislocation substructures attained by thermomechanical processing, therefore they may be considered to take part in improving the high cycle fatigue strength at high temperature.
(iii) Crack propagation rate in the cleavage-like fracture is much slower than that of the succeeding striation area and its mode is considered to be Stage-I fatigue mechanism. As the crack propagation mode and areas are approximately the same irrespective of alloys and temperatures, it is impossible to explain the longer lives at high temperature by the change of the crack propagation mechanism.View full abstractDownload PDF (1459K) -
Ichiro Shiota, Osamu Watanabe1974 Volume 38 Issue 9 Pages 788-794
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNickel layers were plated over yarns and sheets of carbon fibers under various conditions by means of a continuous electroplating process.
The plated layers were observed by an optical microscope and an scanning electron microscope.
Important factors for the preparation of uniform and compact nickel layers were found to be the tension to the yarn, uniformity of the electric current density over the sample in the electrolyte bath, and the setting way of the terminals.
On the carbon fiber yarn, the desirable nickel plating was performed in the case of the same electric current on both inlet and outlet capstans of the electrolyte bath under the condition of nearly tension-free transportation of carbon fiber yarn in the electrolyte bath.
On the carbon fiber sheet, desirable nickel plating was performed when the gradient of current density caused by electric resistance of the samaple was lessened by a suitable setting of the terminals.View full abstractDownload PDF (1118K) -
Ichiro Shiota, Osamu Watanabe1974 Volume 38 Issue 9 Pages 794-800
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStructural changes of carbon fibers coated with nickel were observed during holding at high temperatures.
The inner thin layer of the coated nickel entered into the carbon fiber in the form of a ring at the earlier stages, and moved and aggregated to the center of the fiber. The moving ring in the fiber was found to be nickel metal by X-ray diffraction. The part of the carbon fiber passed by the nickel had a flakey appearance; it should be graphite.
This may be due to diffusion of the carbon atoms in the nickel from the less graphitized (crystallized) part of the carbon to more graphitized part, and deposited carbon atoms crystallize in graphite.
Graphitized carbon fiber is considerably weaker than the original fiber.View full abstractDownload PDF (783K) -
Hiroshi Eda, Kozo Kishi1974 Volume 38 Issue 9 Pages 800-807
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHyper-eutectic aluminium-20% silicon alloy is heat and wear resistant compared to the other aluminium alloys. As in the alloy hard grains are contained in the soft matrix, the mass production of this alloy with high accuracy is very difficult.
The main aim of this investigation is to make clear the deformation and fracture mechanism of the primary silicon crystal and the eutectic phase as a function of the workpiece temperature (θw) in the range from 20 to 300°C by means of the metallographical and plastical studies.
(1) Effective strain (\barε) of the eutectic phase in the machined surface skin layer at θw=300°C increases from \barε=2.0∼2.5 at% θw=20°C to \barε=3.5∼5.0. Furthermore, the effective strain of the machined surface was over \barε=100.
(2) The deformation and fracture of the primary silicon crystal are observed in three typicl types. (i) crashed and partly disappeared silicon, (ii) the cracked one, and (iii) silicon flowing in the direction of machining appear successively in the direction of depth from the machined surface.
(3) The increase in plastic flow in the machined surface layer with rising workpiece temperature depends on the decrease in ductility of the α phase.View full abstractDownload PDF (1143K) -
Takeshi Murakami, Tsuneo Takahashi1974 Volume 38 Issue 9 Pages 807-813
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe orientation changes in the high-purity aluminum single crystal rolled in the (014)[100] orientation were studied by X-ray methods.
During the rolling, three layers having different orientations were found to exist parallel to the rolling plane. In the central layer of the specimen, the lattice tended to rotate toward the (011)[100] orientation, while in the surface layer, it tended to rotate toward the {259}⟨211⟩. A transition layer existing between these two layers did not change its orientation and retained the initial orientation up to 81% reduction, the existence of this transition layer with its unchanged orientation was confirmed by the X-ray measurement. However, at reductions higher than 90%, the formation of recrystallized off-cube grains was found to occur in this layer at room temperature. These grains had the orientation similar to the initial one. The formation of the off-cube texture was consequently, attributed to the mechanism of “oriented nucleation”.View full abstractDownload PDF (885K) -
Effects of Grain Size on the Structure of Oxide Films Formed on 18Cr Steel in High Temperature WaterAkihiko Kitada, Tadayuki Nakayama1974 Volume 38 Issue 9 Pages 813-818
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of grain size on the structures and compositions of oxide films produced on the surface of 18Cr steel heated in water at 300°C for 1 hr were investigated by means of electron diffraction, X-ray microanalysis and ion micromass analysis.
Main results obtained are as follows:
(1) The oxide films produced on the fine grain specimen (ferrite grain size, JIS No. 8) heated in water at 300°C for 1 hr were composed of the corundum type oxides containing Fe and Cr, while on the large grain specimen (JIS No. 1) the oxide films containing Si besides Fe and Cr were produced, and the films consisted of not only the corundum type oxides but also the spinel type oxides.
(2) Regardless of the grain size of the specimen, the oxide films formed on the specimens heated in water at 300°C for 24 hr were composed of the corundum type and the spinel type oxides, and each oxide film contained Si besides Fe and Cr.
(3) Although no difference in the structures of these oxide films due to the grain size was recognized, the amount of Cr in the film was affected by the grain size; Cr in the film formed on the fine grain specimen was much larger in amount than that in the film on the large grain specimen.
(4) In the vicinity of the specimen surfaces, the area where the quantitative ratios of Cr and Si to Fe were decreased by chemical polishing was clearly detected, and the decrease of Si was especially remarkable in the case of the fine grain specimen.View full abstractDownload PDF (875K) -
Hiroshi Nakai, Toshiari Saegusa1974 Volume 38 Issue 9 Pages 819-825
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe initial growth of copper-sulfide formed on the (100), (110) and (111) faces of Cu single crystals in H2S-H2 gas mixture was studied by electron diffraction and electron microscopy. Sulfidation was carried out to form a sulfide film about 1000 Å in thickness at 30°C to 400°C in 500 ppm to 100% H2S.
Main results obtained are as follows:
(1) The sulfide formed on the specimen was alpha (low) chalcocite Cu2S. Not as usual, the chemisorbed layer formed on a clean surface of Cu was regarded as the immediate substrate for the growth of Cu2S, and the following epitaxial relationships were recognized, Cu(100)\varparallelCu2S(012), Cu(110)\varparallelCu2S(001), Cu(111)\varparallelCu2S(001).
(2) The above epitaxial relationships were well maintained at a thinner sulfide film and a higher sulfidation temperature.
(3) It was considered that Cu2S first nucleated as a small orthohexagonal or hexagonal cell and later it grew into a large orthorhombic cell.
(4) Initial sulfidation rate varied with the crystal face and was greater at the (111) face than at (100) and (110) faces.View full abstractDownload PDF (783K) -
Hideo Yoshinaga, Ken Toma, Shotaro Morozumi1974 Volume 38 Issue 9 Pages 826-834
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAverage internal stresses measured by the dip test in high-temperature deformation of Al-Mg alloys have been known to be very high compared with those estimated from the assumption of the equi-distant distribution of parallel dislocations.
In order to examine the validity of the dip test, stress relaxation and rapid strain rate change tests were performed in Al-5.7 at%Mg, and the high internal stresses were confirmed.
The dislocation density and the distribution in the steady-state deformation were estimated theoretically based on the solute atmosphere dragging mechanism, and the average internal stress was calculated from the dislocation distribution. It is concluded that the high internal stress is due to forest dislocations existing in high density.View full abstractDownload PDF (782K) -
Masaaki Naka, Koji Hashimoto, Tsuyoshi Masumoto1974 Volume 38 Issue 9 Pages 835-841
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to evaluate the corrosion resistivity of amorphous iron alloys which have been characterized by outstanding mechanical properties, immersion tests and electrochemical measurements of the amorphous alloys were carried out in acidic and neutral solutions. In a 1 N NaCl solution at 30°C, 0.01–1 N HCl solutions at 30°C and in 10% FeCl3·6H2O solutions at 40 and 60°C, pitting corrosion did not occur on the amorphous Fe-Cr-P-C and Fe-Cr-Ni-P-C alloys and the weight change of the alloys containing 8 at% or more Cr was not detected by a microbalance after immersing for 168 hr.
The critical potential for pitting did not appear on polarization curves of the amorphous alloys and the anodic current higher than 10−7 A/cm2 was not observed over the potential range 0 to 0.5 V (SCE) in 1 N NaCl and 0 to 0.9 V (SCE) in 1 M H2SO4 by the potentiostatic anodic polarization of the alloys containing 8 at% or more Cr. The extremely high corrosion resistivity of the amorphous iron alloys is attributed to the peculiar film formation partly by the presence of Cr and a large quantity of P in the alloys and partly by a single phase of the amorphous state.View full abstractDownload PDF (745K) -
W. S. Tseng, Toranosuke Kawaguchi1974 Volume 38 Issue 9 Pages 842-847
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe severe cold-reduction is necessary for the Fe-Co-Cu-V system alloys to get better properties as semi-hard magnetic materials. The severe cold-reduction, however, is not so easy in practice, that the authors has proposed a new method of intermediate heat-treatment (I.H.) at 550°C between the process of cold-reduction in this investigation. The cold-reduction before I.H. is the primary one, and that after I.H. the secondary one. Magnetic properties are dependent on the primary cold-reduction, secondary cold reduction, intermediate heating temperature, and heating temperature after seconday cold-reduction. This paper has clarified such factors in detail. I.H. treatment not only improves the coercive force by 22% and the remanence by 10%, but also the stability of magnetic properties, as compared with the process without I.H. treatment. The magnetic properties of the sample (63.8%Co, 19.5%Cu, 1.7%V, bal, Fe) with I.H. treatment are Hc 54.5 Oe, Br 15.4 kG, and Br⁄B200 0.97. Such semi-hard magnetic materials are particularly suitable for reed switch pieces.View full abstractDownload PDF (496K) -
Junji Shibata, Masakazu Izutani, Hiroki Kuwahara, Sanji Nishimura1974 Volume 38 Issue 9 Pages 847-852
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe extraction of manganese from an aqueous solution of constant ionic strength with Versatic Acid 911 was studied. The organic phase was a binary solution of Versatic Acid 911 and benzene, and the aqueous phase was composed of Mn(NO3)2 and NaNO3.
It was clarified that both MnR2·4RH and (MnR2·2RH)2 are the predominant extracted species of manganese in the Versatic Acid solution. The following extraction equations and the apparent equilibrium constants were determined respectively:
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (499K) -
Kiyoshi Kita, Hyoe Ono, Hiroshi Nakamura, Syozo Okazaki1974 Volume 38 Issue 9 Pages 852-859
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of the cooling method after tufftriding and of the temperature rise due to the internal friction during the fatigue test on the fatigue strength of tufftrided mild steel (S15CK) were investigated. Ono-type rotating bending fatigue test specimens tufftrided at 570°C for 120 min and cooled with water, oil or air were used. Temperatures of the specimen surfaces were measured by the infrared radiation thermometer.
The results obtained are as follows:
(1) The fatigue strength of S15CK tufftrided specimens varies with the cooling method after tufftriding, that is, the fatigue limits of the tufftrided specimens cooled with water, oil and air are about 43 kg/mm2, 42 kg/mm2 and 39 kg/mm2 respectively, while that of the untufftrided is about 24 kg/mm2.
(2) The surface temperature of the fatigue test specimens rises with an increase of the stress applied and a decrease of the dissolved nitrogen. The maximum temperature of the water cooled test specimen during the fatigue test reached about 250°C under a stress of 55 kg/mm2.
(3) It is expected that the fatigue strength can be increased by cooling the specimen during the fatigue test.View full abstractDownload PDF (1527K) -
Tatsuhiko Ejima, Tsutomu Yamamura, Yoji Arita1974 Volume 38 Issue 9 Pages 859-865
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to clarify the relative importance of the factors controlling the diffusion of ion in molten salt, the diffusion coefficients of 22Na, 86Rb and 134Cs ions in molten sodium chloride and potassium chloride, which are contained in infinite dilution, have been measured by using the capillary reservoir method in the temperature range of 800∼1000°C. The stirring rate of the rod supporting the capillaries and the diameters of the capillaries used are considered to induce large experimental errors when this method is applied to the molten salt system. These effects on the measurement were therefore examined in detail and the diffusion coefficents were determined from the relation of the total diffusate and the diffusion time.
The deviation from the Nernst-Einstein equation in molten sodium chloride is in the range of 20∼30% and increases as the temperature increases. This fact may be explained in terms of the paired vacancy mechanism proposed by Bockris.
The diffusion coefficients of 22Na, 86Rb and 134Cs ions in molten sodium chloride and potassium chloride are in the order of DNa>DRb>DCs which is corresponding to the inverse order of atomic weight and ionic radius of these ions. The apparent activation energies for the diffusion of these solutes increase as the heats of mixing of solutes and solvent salts decrease.View full abstractDownload PDF (601K) -
Yuichi Tanaka, Katsuya Ikawa1974 Volume 38 Issue 9 Pages 865-871
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSome ductile cast irons were up-quenched into an Al bath to refine the structure, and tested at temperatures near their eutectoid transformations to determine whether the superplasticity phenomenon occurs in these materials. Superplasticity was indicated by the high strain rate sensitivity of flow stress at temperatures in the ferrite+austenite+carbon region for M 10 (1%Mn content) and in the austenite+carbon region for M15 (1.5%Mn content). The strain rate sensitivity was not constant for M10 and M15, but it decreased gradually to an value identical to that for M03 (0.3%Mn content) at a higher strain rate. Alloying with Mn expands the temperature region of fine structure, thus permitting a high testing temperature. The void formation at both sides of spheroidal graphite led to premature failure, and therefore the large elongation characteristic of nonferrous superplastic materials did not develop. The ductile cast irons with fine structure have large strength and high ductility at room temperature as compared with the normal structure.View full abstractDownload PDF (979K) -
Effect of Grain Size on the Transformation-Induced Plasticity in Metastable Austenitic Fe-Ni-C AlloyTadashi Maki, Y\={o} Tomota, Imao Tamura1974 Volume 38 Issue 9 Pages 871-876
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of austenite grain size (within the range 5 to 289 μ) on the TRIP phenomenon in metastable austenitic Fe-30%Ni-0.2%C alloy was examined by the tensile test at various temperatures between +80°C and −196°C. The main results are as follows.
(1) The Ms and Md temperatures are lowered with decreasing grain size of austenite, but the amount of decrease in Md is smaller than that of Ms. Then, the temperature difference between Md and Ms (that is, temperature range where the TRIP phenomenon occurs) becomes wider in the specimen with fine grain. Petch-type relation is satisfied between 0.2% proof stress of stable austenite and its grain size. Elongation of stable austenite is also increased with decreasing grain size.
(2) At the temperatures accompanying the TRIP phenomenon, the features of stress-strain curves vary with grain size of austenite. As the grain size decreases, the region at which the strain-hardening rate is small appears just after yielding in the stress-strain curve.
(3) With decreasing grain size of austenite, the temperature range showing TRIP becomes wider and shifts toward lower temperatures, and the maximum elongation value due to TRIP is increased. It was found that the change in maximum elongation with grain size is mainly caused by the change of elongation of stable austenite itself, to which the contribution of grain size by the TRIP phenomenon itself is not so much.
(4) 0.2% proof stress drops at the temperatures around Ms. The temperature range where the TRIP phenomenon occurs becomes wider and the amount of drop becomes larger with increasing strength due to the decrease in grain size of austenite.View full abstractDownload PDF (527K) -
Takashi Yasunaka, Toru Araki1974 Volume 38 Issue 9 Pages 877-883
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStructural changes and the tensile fractures have been studied in an aged Fe-18%Ni-5%Si alloy by means of electron microscopy and tensile tests. It has been concluded that the precipitates in the specimen aged at 350 and 400°C for 6 hr are identified as Fe3Si or (Fe, Ni)3Si having DO3 structure, and on aging at 450 and 500°C for 6 hr as Ni5Si2 or (Fe, Ni)5Si2. In the latter case preferential precipitation occurred at the prior austenite grain boundaries and those of lath martensite besides general precipitation.
The fracture mode of tensile specimens depended on the prior austenite grain size, it changed from dimple fracture to intergranular fracture with increasing grain size. The effective intergranular surface energies in the low- and high-temperature-aged condition were estimated at 7∼8×104 and 2∼4×105 erg/cm2 respectively.
It would appear that one of the causes of the embrittlement of this alloy aged at lower temperature is the result of piling-up dislocations at the grain boundaries due to the difficulty of cross slip, on the other hand the decrease in toughness of this alloy aged at higher temperature is due to the precipitation at grain boundaries.View full abstractDownload PDF (927K)
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