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Volume 28, Issue 5
Displaying 1-10 of 10 articles from this issue
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Michinori Takano, Koji Hashimoto, Wataru Suëtaka, Saburo Shimodai ...1964 Volume 28 Issue 5 Pages 237-244
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is well known that 18-8 stainless steels are much more susceptible to stress corrosion cracking than Inconel in solutions containing chlorine ions.
This work was attempted to find out whether the susceptibility to stress corrosion cracking of these metals depended on the kind of surface films of the alloys or on the dislocation distribution in the alloys. The effect of additional elements on the dislocation distribution in 18-8 stainless steel was also investigated by transmission electron microscopy.
The surface films formed on 18-8 stainless steel and Inconel, which were immersed in pure water or MgCl2 aqueous solution (Cl−; 500 ppm) for 20 hr at 300°C were investigated by reflection electron diffraction and diffuse reflection spectra.
The films formed on both 18-8 stainless steel and Inconel consisted of Ni(OH)2. On the other hand, there was a remarkable difference in dislocation distribution in these metals; in 18-8 stainless steel the dislocations were confined to slip planes and stacking faults were present, while in Inconel the slip was not restricted to a particular direction and cross slip easily was allowed.
From these results, it has been confirmed that the susceptibility to stress corrosion cracking of 18-8 stainless steel is closely related to stacking fault energy.
The effect of additional elements on the dislocation distribution in 18-8 stainless steel was also discussed.View full abstractDownload PDF (1376K) -
Shotaro Morozumi, Michio Kikuchi, Shigeyasu Koda1964 Volume 28 Issue 5 Pages 244-248
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn anomalous fine-grained structure of Mg-Zr alloy phase was observed in the annealed co-extrusion of Mg-0.5%Zr and Mg-1%Al powders.
The present experiment has been carried out to clarify this phenomenon. A cylindrical bimetal billet of pure Mg and Mg-0.5%Zr alloy was extruded at 400°C and the extruded bimetal was annealed at 350°∼550°C for 1, 3 and 9 hr. The grain size of Mg-Zr alloy phase near the interface to the pure Mg phase was measured and plotted in Figs. 2∼4 against the distance from the interface.
The fine-grained zone of about 0.3 mm in the Mg-Zr alloy phase adjacent to the pure Mg phase was observed in the as-extruded condition. Annealing the extruded bimetal at 550°C resulted in remarkable grain growth in the opposite side of this zone to the interface. The fine-grained zone, however, remained in the extent of ∼0.1 mm.
This fine-grained structure of Mg-Zr alloy phase seems attributable not to an ordinary deformation mechanism in the extrusion process of a single billet but to another mechanism caused by the co-extrusion with a softer material.View full abstractDownload PDF (2351K) -
Yoshiyuki Saita1964 Volume 28 Issue 5 Pages 249-253
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe behavior of carbides in the tungsten steel containing 1.45%C 4.86%W during annealing and its effect on subsequent hardening were investigated by means of electrolitic isolation, and chemical and X-ray analyses of carbides. It was found that the carbide phases present in the annealed conditions varied with annealing temperature; M23C6 occured alone in the isothermally annealed specimens at 700°C, which changed partially into M6C and WC after annealing between 800° and 900°C and completely into Fe3C and WC between 1000° and 1200°C. In the commercially hardened condition, the concentration of carbon in the matrix increased progressively with increase of the annealing temperature prior to hardening, but that of tungsten decreased remarkably by the annealing between 900° and 1100°C and oil quenched hardness decreased consequently. It may be concluded that the spoiling of tungsten steel results from a lowering of hardenability due to the decrease of tungsten in the matrix by the carbide changes during annealing.View full abstractDownload PDF (1307K) -
Kaizo Monma, Hajime Suto, Hiroshi Oikawa1964 Volume 28 Issue 5 Pages 253-258
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTensile creep properties of nickel-chromium alloys containing up to 30 at% of chromium have been studied. Tests were carried out in argon atmosphere over the temperature range from 650° to 1150°C, and the stress range from 1.3 to 6.0 kg/mm2. Little changes in general trend of creep curves are observed with increase of the chromium content. The steady state creep rate (\dotεs) decreases with the increasing chromium content. Temperature and stress dependences of the steady state creep rate were analysed using Dorn’s equation, \dotεs=Cσnexp(−Qs⁄RT). Activation energies (Qs) are independent of both applied stress and grain size (from 0.05 to 1.2 mm in average diameters). Qs having a value of 66 kcal/mol for pure nickel scarcely vary with the increasing chromium content at a low concentration range. In alloys containing more than 20 at% of chromium, however, Qs show slightly higher values than of the low concentration alloys (e.g. about 74 kcal/mol for alloys containing 25∼30 at% of chromium). Stress exponents (n), having a value of about 5, show a tendency to decrease slightly with the increasing chromium content.View full abstractDownload PDF (1384K) -
Kaizo Monma, Hajime Suto, Hiroshi Oikawa1964 Volume 28 Issue 5 Pages 258-263
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTensile creep properties of nickel-copper alloys (0 to 100% of copper) have been studied in argon atmosphere in the temperature range between 500° and 1100°C and for the stress range between 1 to 7 kg/mm2. Little changes in general trend of creep curves are observed with the varying composition of alloys. At each temperature, with increase of the copper content, the steady state creep rate (\dotεs) decreases slightly from the value for pure nickel and rearches the minimum value at the concentration of about 30 at% of copper before it increases markedly to the value for pure copper. Temperature and stress dependences of the steady state creep rate were analysed using Dorn’s equation, \dotεs=Cσnexp(−Qs⁄RT). Activation energies (Qs) are independent of both applied stress and grain size (0.05 to 0.7 mm in average diameters). They decrease slightly with the increasing copper content, and decrease markedly in alloys containing more than 80% of copper, approching the value for pure copper. Stress exponents (n) are not exactly constant, but have a value of about 5 for a wide range of composition.View full abstractDownload PDF (1231K) -
Yunoshin Imai, Hiroshi Ichige1964 Volume 28 Issue 5 Pages 264-268
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUsing Mn steel, Mn-Cr steel, Mn-Cr-Ni steel and bearing steel of 5.0 mmφ cylinder, the effects of residual stresses on their oil quenching, water quenching and subzero quenching were investigated by Heyn’s method. Changes in stress due to tempering of these specimens were also measured. Changes in hardness or amount of retained austenite by these heat treatments were also studied. The results obtained are as follows; (1) The distribution of stress in all the specimens showed a stress-transformation type as it change into tension near the surface and compression at the center of the section, and the stress resulting from oil quenching was smaller than that resulting from water quenching.
(2) According to the subzero treatments after oil or water quenched, the hardness was remarkably increased and the amount of retained austenite were clearly decreased, while the distribution of stresses due to subzero treatments changes little.
(3) The residual stress began to decrease by tempering at about 200°C, decreased considerably at about 400°C and disappeared completely at 600°C.View full abstractDownload PDF (1143K) -
Shoji Ueda, Masato Zama, Kenichiro Nakao1964 Volume 28 Issue 5 Pages 269-272
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn a previous paper (J. Japan Inst. Metals, 26 (1962), 348), the-effect of a brittle phase surrounding ductile phase on the yield strength was investigated and the following formula was obtained:
(σ_s - σ_0)^2 = K [{(γ_1 - γ_2)/d}f + γ_2/d:] Where σs is the yield strength, σ0 is the back stress of dislocations, d is the diameter of ductile phase γ1 and γ2 are respectively measures of the strength of ductile/brittle phase boundary and ductile/ductile phase boundary, f is the length fraction of brittle phase boundary and K is the constant.
In copper-aluminium alloy, the ratio γ1 to γ2 in the case of yielding was obtained as follows: (γ_1/γ_2)_yield \simeq2
In the present paper, the relationship between the fatigue strength and the structure was examined using the alloys which were treated under the same conditions as previously reported. The experimental results also satisfied the above mentioned formula in the fatigue strength, and the ratio γ1′ to γ2′ in the case of fatigue rupture was similarily obtained as follows: (γ_1’/γ_2’)_fatigue \simeq2View full abstractDownload PDF (881K) -
Katashi Masumoto, Hiroyoshi Komiya1964 Volume 28 Issue 5 Pages 273-281
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSingle crystals of a semiconducting intermetallic compound ZnSb have been grown by Bridgman’s method and Czochralski’s method. Particularly for Czochralski’s method has been used a very simple apparatus to obtain large single crystals more easily than various complex equipments with some difficult techniques which have been reported so far. This compound crystallizes in the orthorhombic structure, and therefore its semiconducting properties should be anisotropic. Then its electronic and optical properties have been carefully studied in the three principal directions; measurements of the resistivity, Hall coefficient, Seebeck coefficient and the infrared absorption of ZnSb single crystals for these directions have been performed as a function of temperature. The results are as follows: (1) The single crystals of ZnSb thus obtained are quite brittle, cleaving readily on the (100) plane and occasionally on the (001) or (010) plane. (2) All of the single crystals are p-type. (3) The energy gap of 0.56 eV at room temperature is obtained from the slope of intrinsic resistivity curves. (4) For the hole mobility, CT−a law holds approximately between 80° and 300°K, and a is 1.4 to 1.6. (5) The mobility ratio found by the method shown in Fig. 12 is 2.2. (6) The effective mass of holes is calculated to be about 0.19 m0 from Seebeck coefficient data. (7) The infrared absorption gives values for the energy gap for indirect transitions of 0.51 eV at room temperature and 0.61 eV at 0°K. (8) The resistivity, mobility and Seebeck coefficient are found to be anisotropic. The three principal mobilities are in the ratio μ[010]:μ[100]:μ[001]=1:2.6−2.9:4.1−4.5 at the temperature of liquid nitrogen.View full abstractDownload PDF (1871K) -
Eihachiro Tanaka, Sh\={o}z\={o} Semoto, Sadao Watanabe1964 Volume 28 Issue 5 Pages 282-287
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe compressing test has been performed on the cylindrical test pieaces of aluminium, copper, mild steel and stainless steel of 10 mm in dia. ×10 mm in height and aluminium single crystals using various lubricants. The following results are obtained from the relationship between the microscope pattern of the compressed surface and the frictional coefficient: (1) The surface pattern of the plate after rolling are similar to that of the specimen after compressing.
(2) In case of a large frictional coefficient, a glossy surface appears in the specimen in which a greater part of the specimen surface is in contact with tools. In case of a small frictional coefficient, there occurs a dull face having a rugged surface of a few microns in depth. It appeared that there was the fluid film in the sinks.
(3) In the 60% deformation of the various materials with palm oil as a lubricant, the ratio of the exsistence of the fluid film to the total friction surface is 75∼85% for aluminium or copper specimens and about 10% for stainless steel.
(4) From the compressing test it is considered that there are the slip and deformation bands in the rugged surface of the dull face and the lubricants fill them. This phenomenon may be one of the great differences between friction of metal sliding and plastic deformation.View full abstractDownload PDF (1633K) -
Hisashi Suzuki, Masataka Sugiyama, Takateru Umeda1964 Volume 28 Issue 5 Pages 287-291
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWC-Co alloys having 5∼25%Co and various carbon contents were vacuum-sintered and subsequently vacuum-annealed at 600°∼800°C for about up to 50 hr. Some properties of the sintered alloys affected by the annealing were studied noticing their carbon content. Results obtained are summarized as follows:—(1) After annealing, the hardness of alloys does not change; the rupture-strength decreases associated with the slight increase of hardness of binder phase; the lattice constant of the binder, and specific resistivity of the alloys decrease; the microstructure of the binder and its stability for acidic solutions change. (2) These changes in properties result from the precipitation of W atoms from the binder phase during annealing. (3) This is a reason why the properties of the alloys having a lower content of carbon, viz, a higher dissolved W in the binder phase, change remarkably.View full abstractDownload PDF (1279K)
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