Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 36 , Issue 11
Showing 1-20 articles out of 20 articles from the selected issue
  • Hiroshi Kubo, Ken-ichi Hirano
    1972 Volume 36 Issue 11 Pages 1051-1057
    Published: 1972
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    In Ag-Zn alloys containing 27.0∼28.1 wt%Zn, it is found that the bainites which are very similar to the martensites in other noble metal alloys are formed. In order to elucidate its formation mechanism, some fundamental features of the bainitic transformation in the Ag-Zn system are investigated. Optical and electron microscope investigations show that, in Ag-27.6 wt%Zn alloy, bainites are formed slowly and grown in the form of a plate in the temperature range between 180 and 260°C by annealing after quenching from 690°C. The bainites contain many stacking faults and have the habit plane and orientation relationship with the matrix. From the fact that the ordered structures of the matrix is not inherited into the bainites, it is indicated that the bainitic transformation is accompanied with diffusion.
    The temperature range from 180°C to 260°C where the bainitic transformation is observed in the Ag-27.6 wt%Zn alloy can consistently be explained by the shape of the driving force curve vs. temperature. The driving force was estimated from the equlibrium phase diagram considering the ordered state in the matrix.
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  • Hiroshi Kubo, Ken-ichi Hirano
    1972 Volume 36 Issue 11 Pages 1057-1063
    Published: 1972
    Released: April 04, 2008
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    Isothermal annealing of the quenched β-phase of Ag-27.6 wt%Zn alloy in the temperature range between 180 and 260°C produces bainites very similar to the martensites. In order to elucidate the mechanism of the bainite formation, crystallographic features, such as the change in internal microstructures on annealing, the habit plane and orientation relationship between the matrix and the bainites, have been investigated by means of transmission electron microscopy and electron diffraction.
    In the initial stage of annealing at about 240°C, bainites contain many stacking faults. However, on annealing the stacking faults are annealed out. At the same time the flat bainite faces begin to grow outward into a lenticular shape. On the other hand, on annealing at relatively low temperatures such as 200°C, the ζ0-phase precipitates in the bainites.
    The orientation relationship between the matrix (β1) and the bainites with a fcc structure (α) is independent of annealing temperature. As for the close-packed directions and the planes of them, the angle between [\bar111]β1 and [011]α is 1°, and (101)β1 and (1\bar11)α is 3.5°. The pole of the habit plane obtained by the single trace analysis is near {235}β1 with respect to the matrix axes and {258}α with respect to the bainite axes.
    By applying the phenomenological theory of martensite to the present bainite transformation, a good agreement with the experimental results has been obtained.
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  • Masahiro Kitada
    1972 Volume 36 Issue 11 Pages 1064-1069
    Published: 1972
    Released: April 04, 2008
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    The microstructures of Nb-Ti-Zr sheets were investigated to make clear the relation between the microstructures and the applied magnetic field vs critical current density characteristics. The results are summarized as follows:
    (1) The ratio of Jc(\varparallel)⁄Jc(⊥) are in proportion as the ratio of (a+d)⁄a, where Jc(\varparallel) and Jc(⊥) are the critical current densities measured with applied magnetic fields parallel to the rolling plane and perpendicular to the rolling plane, respectively; a and d are the thickness for the “defect layer” and for the “defectless layer”, respectiveley, in the cross-section of the specimen.
    (2) Jc(\varparallel) increases with the increasing tensile strength in the ageing treatment.
    (3) Jc(\varparallel) and Jc(⊥) increase with increasing deformation. The dependence of Jc(\varparallel)⁄Jc(⊥) on the degree of deformation (ε) can be expressed by an empirical formula, Jc(\varparallel)⁄Jc(⊥)∝0.012×ε.
    The relations among the peak effect, the texture, and the microstructures are also discussed.
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  • Yoshio Baba, Michiki Hagiwara, Junji Hamada
    1972 Volume 36 Issue 11 Pages 1070-1074
    Published: 1972
    Released: April 04, 2008
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    In order to improve the resistance to stress-corrosion of Al-Mg alloys containing more than 5% magnesium, effects of additional elements, especially Bi, were investigated. Stress-corrosion tests were carried out on A1-6%Mg and Al-8%Mg alloys containing additional elements, subjected to solution-treatment at 400°C and aging at 130°C for 7 days, in 3.5%NaCl solution at room temperature under conditions of constant load and deflection. The mechanism that the addition of 0.2 to 0.4%Bi reduced the susceptibility of stress-corrosion of the Al-Mg alloys was studied by means of electrical resistivity measurement, EPMA, X-ray diffraction and polarization measurement. The results obtained are as follows:
    (1) Resistance to stress-corrosion cracking Al-6%Mg and Al-8%Mg alloys is greatly improved by the addition of 0.2 to 0.4%Bi.
    (2) Tensile properties, grain size and aging characteristics of Al-Mg alloys containing 0.2 to 0.4%Bi are the same as those of the base alloys.
    (3) The Bi content exists as an insoluble compound Bi2Mg3 and makes the potential of the base alloy less noble. The favorable effect of Bi addition may be due to the sacrificial protective action of the electronegative Bi2Mg3 compound.
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  • Yoshio Baba, Michiki Hagiwara, Junji Hamada
    1972 Volume 36 Issue 11 Pages 1075-1081
    Published: 1972
    Released: April 04, 2008
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    An Extensive study has been undertaken to develope new wrought Al-Mg alloys which have excellent resistance to corrosion and stress corrosion cracking with high strength. The stress corrosion properties of 5083 (Al-4.5%Mg-MnCr), Al-4.5%Mg-MnCrBi, Al-6%Mg-MnCrBi and Al-6%Mg-CuZr alloys manufactured under field operations, have been investigated by the U-bend method in 3.5%NaCl solution at room temperature for one year.
    Prolonged aging at 130°C after water-quenching from 400°C, followed by about 30% of cold reduction, decreases most severely the resistance to stress corrosion of 5083 alloy. On the contrary, furnace cooling from the solution temperature and warm working at 200∼250°C with 50% reduction in thickness increase the resistance to stress corrosion of 5083 alloy.
    A new wrought alloy Al-6%Mg-MnCrBi has superior strength and resistivity to stress corrosion similar to those of 5083 alloy, while Al-4.5%Mg-MnCrBi alloy has superior resistance to stress corrosion with similar strength. The resistance to stress corrosion of Al-6%Mg-CuZr alloy is slightly inferior to those of the above-mentioned alloys.
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  • Takaaki Ôshita, Hideo Takei
    1972 Volume 36 Issue 11 Pages 1081-1086
    Published: 1972
    Released: April 04, 2008
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    The effects of strain-rate and drawing temperature on the drawing force and the mechanical properties of a superplastic Zn-Al alloy drawn under various conditions were investigated, compared with those of the annealed non-superplastic alloy of the same composition. The results obtained are as follows:
    (1) The drawing force required for the superplastic Zn-Al alloy which was water quenched from 380°C after being heated for 1 hr (named the water quenched material) and the non-superplastic alloy of the same composition which was air cooled from 380°C after being heated for 1 hr (named the annealed material) decrease linearly with the rise in drawing temperature, and those values are minimum at eutectoid point 275°C. The drawing force increases with the strain-rate.
    (2) Under the same condition, the drawing force for the water quenched material is always smaller than that for the annealed material.
    (3) The maximum value of the drawing ratio for the water quenched material is larger than that for the annealed material. At too high a strain-rate, the blank prepared from the water quenched material breaks for lack of ductility (or of strength at temperatures higher than 200°C). At too low a strain-rate, it breaks from the lack of strength.
    (4) The upper and lower limits of strain-rate for deep drawability become larger as the drawing temperature rises. They show the largest value at 200 and 250°C respectively and then decrease as the temperature rises. The range of strain-rate for deep drawability is most extensive at 150∼200°C and most narrow in the neighborhood of room temperature and 250°C.
    (5) The compressive strength and hardness of the products drawn from the water quenched material increase with the rise in drawing temperature. The homogeneity of the products made of the water quenched material is higher than that of the products made of the annealed material.
    (6) Strength of the products drawn from the water quenched material can be improved by annealing (air cooling from 380°C after being heated for 1 hr).
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  • Yoshio Waseda, Masayasu Ohtani
    1972 Volume 36 Issue 11 Pages 1087-1092
    Published: 1972
    Released: April 04, 2008
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    Recent neutron diffraction data for liquid neon and X-ray diffraction data for liquid sodium have been analyzed for the purpose of studying the pressure dependence of the structure in these liquids by means of the method proposed by Egelstaff, Page and Heard. In both cases, it was found that the function \ ildeH(Q), which expresses the deviation from the superposition approximation, is not zero, though the pressure derivative of the structure factor gives little contribution to the function \ ildeH(Q). Therefore, the superposition approximation is not necessarily sufficient for the description of the triplet correlation function in liquid neon and sodium.
    Besides, the pair potentials have been calculated from these diffraction data at various pressures using the Born-Green equation. The pair potentials obtained for three states of liquid neon are of the Lennard-Jones type, whereas those obtained for liquid sodium with a provisional assumption based on the experimental results are of the long-range oscillatory type. The difference in the pressure dependence of the structure factor for liquid neon and sodium can be explained by the pair potential functions calculated in this work.
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  • Hideyuki Yoshikoshi, Masanori Tokuda, Masayasu Ohtani
    1972 Volume 36 Issue 11 Pages 1093-1100
    Published: 1972
    Released: April 04, 2008
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    The nucleation and growth of the iron phase on wustite during the reduction with H2-N2 or CO-N2 at 650∼850°C and the properties of iron reduced were investigated.
    The results obtained are as follows:
    (1) The nuclei originated from pores and edges on the wustite surface in the H2-N2 reduction. On the other hand, they originated mostly from edges in the CO-N2 reduction. In either gases an iron nucleus on wustite grew linearly against the reduction time.
    (2) The rate of iron growth on wustite was proportional to PH2 in the range of PH2=0∼0.2 atm. The reproducibility of the rate of iron growth in CO-N2 was worse than that of H2-N2 reduction. The rate of iron growth was proportional to PCO in the range of PCO=0∼0.8 atm and kept nearly constant over PCO=0.8 atm.
    (3) The apparent activation energy for iron growth on the wustite surface was about 14 kcal/mol in H2 and fluctuated in the range of 16∼32 kcal/mol with CO concentration in CO-N2. The rate of iron growth in H2 was nearly 40 times larger than that of CO at the same partial pressure of reducing gas.
    (4) The iron reduced in H2 was very dense at the FeO/Fe interface and the iron growth into the wustite bulk was not appreciable. On the other hand, the iron reduced in CO was porous and the iron growth into the wustite bulk was remarkable.
    (5) The rate of iron growth in H2 was controlled by an interfacial reaction at the FeO/Fe/H2-three phase boundary on the wustite surface. At the beginning of CO reduction the iron growth took place at the FeO/Fe interface both on the surface and inside the specimen, because the porous structure of iron and CO2 formed by the reduction of FeO affected the rate of iron growth on wustite. Wide scattering of the data of iron growth in CO reduction may be attributed to the effect of CO2 from the FeO/Fe interface inside the FeO bulk.
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  • Yasunori Tanji, Hajime Asano, Hiroshi Moriya
    1972 Volume 36 Issue 11 Pages 1100-1104
    Published: 1972
    Released: April 04, 2008
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    Specific heats at constant pressure, Cp, of Fe-Ni (fcc) alloys have been measured at temperatures 300∼1000 K. For the alloys containing more than 50% nickel, Cp shows a sharp λ-type peak at the ferromagnetic Curie temperature. For the alloys containing less nickel, however, only a dull peak is observed. The Cp-T curves are analysed using the values of thermal expansion coefficients and compressibilities measured on the same conditions, so that the magnetic contribution is separated from the total specific heats.
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  • Shitoshi Ohtani, Takashi Nishimura, Minoru Nishigaki
    1972 Volume 36 Issue 11 Pages 1105-1110
    Published: 1972
    Released: April 04, 2008
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    The precipitation site of alpha, which is related to the mechanical properties of the aged Ti-Mo base beta alloys is, as previously reported, affected by the preceding solution-treatment. It seems that this phenomenon is related to the recrystallization behavior of the alloys. The effects of the preceding working and the solution-treatment on the precipitation site of alpha during aging were studied in Ti-15Mo-5Zr and Ti-15Mo-5Zr-3Al alloys.
    The beta transus was determined using an optical microscope. By observing the structure after heat treatment at temperatures above or below the estimated beta transus, the precipitating or vanishing point was determined. Detection of a small quantity of alpha on the grain boundaries was difficult. Consequently the specimens in which alpha was uniformly precipitated in the grains by pre-aging, were examined. The beta transi of Ti-15Mo-5Zr and Ti-15Mo-5Zr-3Al obtained in the present study were 730 and 785°C respectively.
    Two steps of recrystallization were observed in the alloys. Alpha precipitated non-uniformly during aging even in the specimens, in which most of the deformed grains were changed to equiaxed ones in the initial stage of recrystallization. The fact that alpha precipitated in some grains and not in others is due to the incompleteness of the recrystallization. Alpha precipitated preferentially on the grain boundaries after the final stage of recrystallization.
    The relation between the temperature and the time of the two stages of recrystallization is summarized in a diagram. The final stage recrystallization temperature was affected by the preceding deformation conditions.
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  • Hakaru Masumoto, Michio Kikuchi, Shôhachi Sawaya
    1972 Volume 36 Issue 11 Pages 1111-1115
    Published: 1972
    Released: April 04, 2008
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    Measurements of thermal expansions and Young’s moduli at −150∼500°C have been carried out for single crystal specimens, 3 mm in diameter and 120 mm long, of Co-Elinvar. At the same time the rigidity modulus of a polycrystal of the same alloy has been measured at room temperature. The Young’s moduli at 20°C obtained are 9.45×105, 19.47×105 and 30.12×105 kg/cm2 in the ⟨100⟩, ⟨110⟩ and ⟨111⟩ directions, respectively, while the rigidity moduli are 16.71×105, 5.93×105 and 4.88×105 kg/cm2 in the three principal directions, respectively. In both cases, the elastic anisotropies are very large. The Young’s modulus vs temperature curves in the three principal directions show a small maximum at temperatures below the magnetic transformation point. The mean temperature coefficients of Young’s moduli at 0∼40°C in the three principal directions are e⟨100⟩=−0.47×10−5, e⟨110⟩=−3.40×10−5 and e⟨111⟩=−6.77×10−5, respectively.
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  • Hakaru Masumoto, Shôhachi Sawaya, Michio Kikuchi
    1972 Volume 36 Issue 11 Pages 1116-1120
    Published: 1972
    Released: April 04, 2008
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    Measurements of Young’s moduli at −150∼400°C and of rigidity moduli and hardness at room temperature have been carried out with Mn-Ni-Co alloys subjected to a various procedure of heat treatment and cold working. On Young’s modulus vs temperature curves, the ternary alloys slowly cooled after heating for 1 hr at 950°C showed a distinct anomalous change associatiated with the antiferromagnetic\ ightleftarrowsparamagnetic transformation. Young’s moduli at room temperature did not show a large difference by the annealed, cold worked and water quenched states and also by the alloy composition, but the temperature coefficients of Young’s moduli were greatly changed. It is to be noted that the temperature coefficients of Young’s moduli as a function of composition exhibited a large positive maximum, thus revealing the Elinvar property. The variation in rigidity modulus and its temperature coefficient with heat treatment, cold working and composition showed a close similarity to that in Young’s modulus and its temperature coefficient. The hardness is changed in a very complicated way by the heat treatment, cold working and alloy composition; the Vickers hardness is between 100 and 800. However, the corrosion resistance of Mn-Ni-Co alloys was relatively good.
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  • Renpei Yoda, Takehiko Itagaki
    1972 Volume 36 Issue 11 Pages 1121-1124
    Published: 1972
    Released: April 04, 2008
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    Although the refractorymetals typified by W, Ta and Mo show good mechanical properties at high temperature, their application is greatly limited because of their poor oxidation resistance. In this paper, oxidation properties of the W-Ta system were investigated. Samples were prepared by means of electron beam melting. The results are summarized as follows:
    (1) All of the W-Ta alloys showed lower oxidation rates than pure W and Ta.
    (2) Addition of 5%Ta to the W brought about a remarkable reduction oxidation rate, and the decrement remained almost unchanged until the addition of 30%Ta. The scale of these alloys consisted of WO2.90.
    (3) The lowest oxidation rate was attained at the composition of W-40∼50%Ta, and its oxidation product was 3WO3·Ta2O5.
    (4) Although the scale of these alloys was generally porous and had poor adherency with the metal matrix, only W-70%Ta alloy formed a compact and strong adheasive scale. But this W-70%Ta alloy was broken at the grain boundary when it was held for 30∼40 min at 1000°C in oxidation atmosphere.
    (5) W and Ta alloys make a continuous solid solution and the lattice parameters of the alloys used in this investigation also supported this fact, but the hardness curves of our specimens showed abnormality.
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  • Osamu Akisue, Kikuo Takashina
    1972 Volume 36 Issue 11 Pages 1124-1130
    Published: 1972
    Released: April 04, 2008
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    The effects of Niobium on the cold-rolling and recrystallization textures in low carbon steel sheets were examined using X-ray techniques and electron microscopy. In the hot-rolled strips containing Niobium, numerous precipitates (about 150 Å in diameter) were observed. These precipitates influenced the cold-rolling textures and gave the tendency to increase the {111} component with cold reduction up to 75%. The {111} component decreased abruptly and the {211}⟨011⟩ component increased for reductions greater than 75%. The recrystallization textures could be closely related to the cold-rolling textures. The recrystallization textures changed continuously from {544}⟨225⟩ to {211}⟨011⟩ along the loci of R.D. −60°\varparallel⟨110⟩ fiber texture with cold reduction prior to annealing. It was also found that fine precipitates retarded the recrystallization and inhibited the appearance of the (110)[001] component.
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  • Nobuyuki Morito, Wataru Suëtaka
    1972 Volume 36 Issue 11 Pages 1131-1140
    Published: 1972
    Released: April 04, 2008
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    High-sensitivity infrared reflection spectra were used to analyze the structure and thickness of oxide films on copper mirror and the corrosion protective films formed on metal by benzotriazole. Infrared oxide band intensities were found to be directly proportional to the oxide film thicknesses over the range of several tens to several thousands of angstrom. Even in the case where the surface film is composed of more than two compounds, the film thickness of each compound can be determined by this method.
    In oxidation treatments in air, the growths of cuprous oxide (645 cm−1) and cupric oxide (560 cm−1) films obeyed the direct logarithmic kinetics at about 150 to 200°C. Some copper specimens were oxidized in air after immersing in 3%NaCl aqueous solution (pH 3, 25°C) containing 0.02 M benzotriazole (BTA). At about 200°C the air oxidation was inhibited effectively by this BTA treatment, but over 250°C the treatment became not effective. The proposed mechanism of inhibition due to the BTA treatment is that the ionization of copper atoms is retarded at the interface between metallic copper and benzotriazole-cuprous salt (BTA-Cu(I)) film. This is supported by the facts that (1) the oxidation of copper treated by BTA also obeyed the logarithmic kinetics, (2) the oxidation rate was independent of the film thickness of BTA-Cu(I), (3) and the oxidation products Cu2O and CuO were formed as the outer layer of BTA-Cu(I) films.
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  • Takashi Kuse, Naoji Iwai, Yasunobu Hirasawa
    1972 Volume 36 Issue 11 Pages 1141-1145
    Published: 1972
    Released: April 04, 2008
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    Oxidation films of Fe-42Ni-6Cr alloy used for sealing of soft glass have been investigated. Oxidation of the alloy was carried out in air and in wet hydrogen. The results obtained are as follows.
    (1) In the case of oxidation of the alloy is carried out in air, the oxidation film consists chiefly of α-Fe2O3 and Fe3O4, and the activation energy of oxidation changes at about 1000°C.
    (2) In wet hydrogen, the oxidation film consists chiefly of Cr2O3 and (Fe, Mn)O·Cr2O3. The activation energy for oxidation is 28 kcal/mol and is nearly indepent of the humidity of hydrogen. The oxidation rate constant changes in proportion to the exponent of 1/2.5 of a partial pressure of oxigen and is almost independent of oxidation temperature.
    (3) In wet hydrogen, in the initial stage of oxidation, the grain boundary of the alloy hill up. As the oxidation proceeds, the boundary becomes undistinguishable from the bulk, and three different whiskers of oxide have grown on the bulk. Those are the hill type, the needle type and the needle type with spherical crystallines on the top.
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  • Hideo Abe, Kazumasa Togano, Hirokazu Sugawara
    1972 Volume 36 Issue 11 Pages 1146-1151
    Published: 1972
    Released: April 04, 2008
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    Cold rolling and annealing textures have been observed in double-oriented ingots of Al-3%Cu alloy cold rolled by 90% in the (100)[001] orientation, (A) after solution-treatment at 520°C for 48 hr and quenching into water, (B) after ageing at 190°C for 48 hr, or (C) after ageing at 250°C for 15.5 hr.
    The cold rolling texture of specimen A rolled immediately after the quenching contains a preferred orientation of near (112)[11\bar1], that of specimen B contains (210)[001] and (320)[001] orientations, and that of specimen C contains an orientation near {7,12,22}⟨84\bar5⟩.
    The intensity of cube texture component retained after cold rolling is in the order A<B<C, whereas the intensity of the same component contained after primary recrystallization is in the order A>B>C.
    The orientation changes during rolling and the orientation relationship between the rolling and recrystallization textures are discussed on the basis of the geometrical analysis of slip-rotation, the oriented growth theory and the oriented nucleation theory.
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  • Hirohiko Omura, Kouiti Furusawa, Kazuhide Tanaka
    1972 Volume 36 Issue 11 Pages 1151-1155
    Published: 1972
    Released: April 04, 2008
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    Deformation behaviors of cementite and ferrite in eutectoid steel have been studied using an X-ray diffraction technique. The peak-shifts and the variation of integral breadth of (112·021), (121) and (211) lines of cementite and (110), (200) and (211) of ferrite in bulk materials were chiefly investigated after tensile deformation or cold rolling. The residual strain in each of these phases was clarified to be composed of a uniform strain and a nonuniform part which varied significantly with the degree of deformation. The results were compared with those on the electrolytically isolated cementite as well as with the observation by carbon replica electron microscope, and are summarized as follows.
    (1) In lamellar cementite the line broadening occurs remarkably above 12% elongation in tensile deformation or 4% reduction in cold rolling. On the other hand, globular cementite shows only a weak increase of the breadth in both tensile and rolling deformations. The broadening possibly related with the fragmentation of the cementite.
    (2) Concerning the isolated cementite the broadening of diffraction lines begins to appear above 19% reduction in lamellar material. However, it never occurred in the globular one even under 50% reduction.
    (3) The line broadening behavior of ferrite in the eutectoid steel is very similar to that of low carbon steel.
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  • Makoto Kassai, Masanori Okada, Tatsuji Sasaki, Zenzo Henmi
    1972 Volume 36 Issue 11 Pages 1156-1157
    Published: 1972
    Released: April 04, 2008
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  • 1972 Volume 36 Issue 11 Pages 1157
    Published: 1972
    Released: April 04, 2008
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    Please see PDF Wrong:Photo. 3, Fig. 4 Right:[Please see PDF], [Please see PDF]
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