Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 40 , Issue 4
Showing 1-18 articles out of 18 articles from the selected issue
  • Koji Yamaguchi, Kenji Kanazawa
    1976 Volume 40 Issue 4 Pages 315-320
    Published: 1976
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The submicroscopic structures of Type 316 stainless steel low-cycle fatigued at elevated temperatures up to 800°C are examined by means of transmission electron microscopy and their correlation with the fatigue behavior is discussed.
    \ oindentThe results obtained are summarized as follows:
    (1) The dislocation substructure below 600°C is the cell-type and that above 700°C is the subgrain-type. Above 700°C, the recovery process begins and progresses.
    (2) It is found that the cell or subgrain diameter (d) depends solely on the saturation stress range (Δσ) and the relation between them is given by Δσ⁄Gd−0.5 where G is the shear modulus.
    (3) It is considered that large cyclic-hardening observed at 450°C and 600°C and the negative strain-rate dependence of the saturation stress range at 450°C are related with the P-L effect, and that they are not due to precipitation of carbides but to the dragging effect of dislocations by solute elements.
    (4) The increase of fatigue life with increasing temperature between 600°C and 800°C for smaller strain rates and a larger strain range is thought to be caused by recovery of the material during fatigue testing.
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  • Hiroyasu Mitani, Kazuhiko Majima, Yuko Hanatate
    1976 Volume 40 Issue 4 Pages 320-327
    Published: 1976
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Using mixed powder compacts of Fe-8.0%Cu-C ternary system with different graphite contents, and Fe-Cu-1.0%C ternary system with different Cu contents, a study of the effect of graphite content on the elimination of the abnormal expansion during the heating process of the Fe-Cu binary mixed powder compacts was carried out mainly by the differential dilatometric method.
    The results obtained were as follows:
    (1) In the mixed powder compacts of the Fe-8.0%Cu-C ternary system with graphite contents up to 0.6%, the abnormal expansion persisted through out the sintering process in the γ region, although the amount of expansion was smaller than that of the Fe-8.0%Cu binary system.
    However, the specimens with the graphite content more than 0.8% showed a maximum expansion at a temperature slightly higher than 1090°C and then shrank at higher temperatures.
    (2) Dimensional change of the Fe-8.0%Cu-C ternary compacts subjected to isothermal sintering at 1150°C for 60 min decreased with increasing graphite content.
    For example, the residual expansion rate of the Fe-8.0%Cu binary system was 2.8%, while it was 1.05% for the specimen with 0.6%C and 0.05% for the specimen with 1.0%C, respectively. Furthermore, shrinkage was observed with the specimens containing more than 1.2%C.
    (3) The maximum expansion rate of the Fe-Cu-1.0%C ternary mixed powder compacts increased nearly in proportion to Cu content up to 6.0% but remained constant at higher Cu content.
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  • Kazuhiko Majima, Hiroyasu Mitani
    1976 Volume 40 Issue 4 Pages 327-333
    Published: 1976
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    In the previous paper, we confirmed that the Fe-8.0%Cu-C ternary mixed powder compacts containing more than 0.8%C, and the Fe-Cu-1.0%C ternary mixed powder compacts containing more than 4.0%Cu showed shrinkage on heating at the temperature higher than 1090°C.
    In this experiment, a study of the elimination mechanism of the abnormal expansion by graphite addition was carried out mainly from the viewpoint of the Fe-Cu-C ternary equilibrium.
    The results obtained were as follows:
    (1) The Fe-8.0%Cu-C ternary mixed powder compacts containing up to 0.6%C showed only one endothermic peak due to Cu melting at 1083°C during the heating process. However, in the specimen containing more than 0.8%C, another endothermic peak due to the ternary monotecto-eutectic reaction at 1095°C was observed, in addition to the above mentioned endothermic peak.
    During the cooling process, the Fe-8.0%Cu binary mixed powder compacts showed, no exothermic peak due to solidification. While the Fe-8.0%Cu-C ternary mixed powder compacts containing up to 0.6%C showed the exothermic peak due to the solidification of Cu at 1083°C, the specimens containing more than 0.8%C showed the exothermic peak due to the ternary monotecto-eutectic reaction.
    (2) The Fe-Cu-1.0%C ternary mixed powder compacts containing 3.0%Cu showed only one endothermic peak due to Cu melting at 1083°C during the heating process. The specimens containing more than 4.0%Cu showed another endothermic peak due to the ternary monotectoeutectic reaction at 1095°C, besides the peak due to Cu melting.
    During the cooling process, as for the specimens containing up to 4.0%Cu, no exothermic peak due to solidification was observed, while the specimens containing more than 6.0%C showed the exothermic peak due to the ternary monotecto-eutectic reaction at 1095°C.
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  • Hirofumi Miyaji, Satoshi Watanabe
    1976 Volume 40 Issue 4 Pages 334-341
    Published: 1976
    Released: April 04, 2008
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    The effects of solute carbon, grain boundary, martensite phase and precipitates on the development of the texture of 17Cr stainless steel sheet were investigated on the specimens containing different amounts of carbon and copper. The obtained results were as follows:
    (1) The main component {100}⟨011⟩ of the hot-rolling texture increased remarkably in the presence of solute carbon.
    (2) The {211} and {222} components of the cold-rolling texture of the steel with 1.1%Cu were considerably developed by the number of fine ε-Cu precipitates generated through the precipitation treatment.
    (3) The hot rolled sheet contains some amount of the martensite phase by the addition of about 0.04%C and when cold rolled directly and annealed, a scatter of orientation in those steel sheets was observed.
    (4) The {222} component of recrystallization texture was most remarkably developed in the sheet containing about 0.6%Cu, but in the presence of carbon, the {200} component was recognized considerably.
    (5) The cold-rolling texture remained even after the final annealing when a large amount of fine ε-Cu precipitates was dispersed by the addition of about 1.1%Cu.
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  • Hirofumi Miyaji, Satoshi Watanabe
    1976 Volume 40 Issue 4 Pages 341-345
    Published: 1976
    Released: April 04, 2008
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    The athermal recrystallization process was observed to investigate the mechanism of the development of the {111}⟨112⟩-type recrystallization texture by the addition of 0.57%Cu to 17Cr stainless steel sheet. From the obtained results it was presumed that the fine ε-Cu precipitates affected the recovery and recrystallization processes, resulting in a suppression of a high angle grain boundary migration of {110}⟨001⟩-oriented grains nucleated mainly in the {111}⟨112⟩-oriented deformed crystals, and the development of in situ recrystallization of the {111}⟨112⟩-oriented grains was induced.
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  • Shozo Yoshioka, Eiichi Sukedai
    1976 Volume 40 Issue 4 Pages 346-352
    Published: 1976
    Released: April 04, 2008
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    Knoop indentations and Vickers ones are made on cube faces of Cu single crystals and the distributions of dislocations introduced by making indentations are three-dimensionally examined by the etch pit technique. Influences of adjacent indentations and specimen edges on the indentation hardness values are investigated by observing dislocation distributions in indentations. The results obtained are as follows:
    (1) Distributions of slip traces and dislocations in Vickers indentation are similar to those in the conical one.
    (2) Dislocation density of high dislocation density regions in the Knoop indentation as well as the Vickers one is of the order of 108 cm−2.
    (3) The hardness value is influenced by a neighboring indentation when high dislocation density regions overlap.
    (4) The hardnes values are affected by a side surface when the high dislocation density region of an indentation is influenced by the side surface.
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  • Imao Tamura, Katsuyuki Isogami, Tadashi Maki, Syoji Fujiwara
    1976 Volume 40 Issue 4 Pages 353-360
    Published: 1976
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The aging behavior of Fe-30Cr-8Ni alloy having two phases of α and γ with a microduplex structure or coarser structure was studied by means of optical microscopy, hardness measurements and the tensile test.
    (1) On aging at 475°C, the strength was increased by spinodal decomposition of α-phase. In the coarser structure, α became deformed by mechanical twinning with aging. In the microduplex structure, α was deformed by slip and the elongation did not decrease so much in spite of aging for a long time, because α was difficult to be deformed by mechanical twinning owing to a fine microstructure and the strain hardening rate of the alloy was increased by preferential deformation of γ.
    (2) On aging at 650 or 750°C, the transformation of grain boundary reaction type: α→γ*+σ (γ*: new γ-phase), occurred. This transformation was progressed by the lamellar growth in the coarser structure but in the microduplex structure by the growth of a domain consisting of γ* and σ instead of lamella. There was a marked fluctuation in hardness at an early stage of hardening in the microduplex structure. The alloy was embrittled with this type of transformation and γ had no effect on the enhancement of ductility.
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  • Kyoko Fujii, Toshio Katagiri, Eiichi Takeuchi, Kazushige Chiba, Takuro ...
    1976 Volume 40 Issue 4 Pages 360-366
    Published: 1976
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    This paper deals with the wear characteristics and the mechanism of sliding wear, under unlubricated conditions of boride layers, FeB and Fe2B formed on S45C steel by gas boronizing.
    The results showed that wear characteristic curves of FeB and Fe2B layers gave similar patterns, and that the wear conditions, under which the maximum wear rates were observed, were 0.30 m/sec in sliding velocity for the FeB specimen and 0.50 m/sec for the Fe2B specimen. Under these wear conditions, the mechanical wear caused by scratching and oxidative wear coexisted. Under mild wear conditions, oxidative wear preferentially occurred and destruction of the sliding surface was brought about by thermal stress under heavy wear conditions.
    From the results of X-ray diffractions, it was found that the wear debris were chiefly composed of iron oxides (α-Fe2O3, Fe3O4) formed by the oxidative wear and α-Fe and borides (FeB, Fe2B) scratched by the mechanical wear.
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  • Takurô Nakamichi, Tokujirô Satô, Yukio Nagayama
    1976 Volume 40 Issue 4 Pages 366-375
    Published: 1976
    Released: April 04, 2008
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    Single Crystals of two kinds of spinel-type oxide have been grown by the Verneuil method. (Mg, Mn)O-Al2O3 showed a distinct growth hillock on the top of the crystal and a characteristic distribution of dislocations. A more or less regular network of subboundaries is observed in the cross section, suggesting the presence of an easy atomic movement along the ⟨110⟩ direction which is not vertical to the growth direction and is located near the solid liquid interface in the growing process. This assumption explains the observed character of the growth hillock and of the internal structure, as being due to a polygonization of remaining edge dislocations. The characteristic of side planes observed in grown crystals of MgO-2.5Al2O3 as reported by Nakano et al. may also be explained by the same assumption. A single crystal of Fe3O4 was grown successfully. However, it contains a small amount of precipitates of α-Fe2O3.
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  • Yuichi Tanaka, Katsuya Ikawa
    1976 Volume 40 Issue 4 Pages 375-381
    Published: 1976
    Released: April 04, 2008
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    Two ductile cast irons were heat-treated to refine the matrix grains and tensile creep tested mainly at temperatures in the ferrite+austenite region. In the iron having a fine grained matrix structure consisting of ferrite and austenite, superplasticity was indicated with a high strain rate sensitivity m of flow stress σ at a low strain rate (\dotε<2×10−4 min−1). At a constant strain rate corresponding to maximum m, it was found that σ was proportional to \barL, the metallographic mean free path of grain boundaries. To account for this particular relation of σ with \barL, grain boundary shear was proposed as the deformation process which permits a greater contribution to the total deformation during superplastic deformation.
    In the eutectoid transformation temperature region, it was observed that increasing the amounts of ferritic phase lowers the flow stress at all strain rates because the ferritic iron is weaker than the austenitic one. The strain rate sensitivity is markedly influenced by the amount of eutectoid transformation at a low strain rate, i.e., under the creep test which involves the transformation, a high strain rate sensitiviy was observed (m=0.52∼0.62).
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  • Yasunori Taga, Koichi Nakajima
    1976 Volume 40 Issue 4 Pages 382-386
    Published: 1976
    Released: April 04, 2008
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    The effects of phosphorus on the friction and wear characteristics of Cu-5 at%Sn-P alloys containing 1∼5 at%P were studied using the pin on disc apparatus.
    The results showed that the decrease in both the coefficient of friction and the rate of wear became conspicuous with the increase in quantity of Cu3P coexisting in the matrix; its amount increases with the content of phosphorus. The structural changes in the surface of the specimen due to heating in vacuum were observed by using Auger electron spectroscopy; it was seen that the surface concentration of phosphorus strongly increased after heating at 300°C, while the diffusion of tin atoms was markedly retarded.
    It was concluded from these results that the behavior of phosporus atoms in the surface during sliding played an important role in controlling the friction and wear characteristics of Cu-Sn-P alloys.
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  • Kazuo Kameda, Senzi Sakairi, Yoshio Yoshida
    1976 Volume 40 Issue 4 Pages 387-392
    Published: 1976
    Released: April 04, 2008
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    The values of E.M.F. of liquid Au-Tl and Au-Pb systems were measured in the temperature ranges from 700 to 800°C and 700 to 950°C respectively, by using galvanic cells composed of
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    noindent and
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    \ oindentrespectively. The values of E.M.F. obtained in both systems showed good stability and linear relationship with temperature.
    The activities of both components in these systems demonstrate moderate negative deviation from Raoult’s law over the whole concentration range.
    The maximum values of the heat of mixing are −0.06 kcal/mol for the Au-Tl system at NTl=0.60 and −0.21 kcal/mol for the Au-Pb system at NPb=0.59. The small temperature dependencies of the activities in these systems correspond to these small values of the heat of mixing.
    In addition, some other thermodynamic functions were derived from the results obtained.
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  • Katunori Abe, Hideo Yoshinaga, Shotaro Morozumi
    1976 Volume 40 Issue 4 Pages 393-399
    Published: 1976
    Released: April 04, 2008
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    Applicability of the stress relaxation test as a method of discerning frictional stress and internal stress is examined theoretically. It is found that the strain rate should change continuously on the onset of stress relaxation when an appreciable amount of frictional stress exists, while the strain rate should change discontinuously at the starting point of the stress relaxation when the frictional stress is negligibly small or the internal stress is the dominant component of the flow stress. Whether the contribution of the frictional stress to the flow stress is appreciable or not, can therefore be determined by comparing the strain rates immediately before and after the start of the stress relaxation.
    By applying this method to the experiment of high-temperature deformation of metals and alloys, the following results are obtained: In pure aluminium and vanadium, the frictional stress is negligibly small, that is, the flow stress is almost equal to the internal stress. Meanwhile, in solution-hardened alloys, Al-5.7 at%Mg and V-5.0 at%Fe, the frictional stress appreciably contributes to the flow stress.
    Merits and demerits of the proposed method are discussed comparing with the usual methods for measuring the internal stress.
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  • Naotake Niwa, Tadatsune Okubo
    1976 Volume 40 Issue 4 Pages 399-405
    Published: 1976
    Released: April 04, 2008
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    The process of “double-cup” fracture was examined in vacuum melted copper round bar specimens pulled in tension and compared with that of “cup and cone” fracture in a previous paper.
    Longitudinal sections of specimens strained to various points on the load vs elongation curve were examined by optical microscopy. Neither inclusions nor voids are found even in the central region of the specimen pulled far beyond the maximum load point. This type of fracture was completed through the following stages. (1) When the straining of the specimen approaches a steep load drop point on the load vs elongation curve, voids are formed and the number and size of voids increase. Deformation gradually concentrates into narrow zones and causes the separation of these zones, resulting in the formation of a few small cracks. This is the onset of the fracture (so-called “break-point”). (2) Connecting these small cracks, a large central crack is formed. It grows gradually in zig-zag steps toward the outer surface of the specimen. These two stages of the “double-cup” fracture and the characteristics of the load vs elongation curve of these stages are phenomenologically the same as those in the “cup and cone” fracture. (3) During growth of the central crack, narrow regions of heavy deformation extend from the crack tip to the outer surface. In the “cup and cone” fracture these regions are separated and the crack tip reaches the outer surface. In the “double-cup” fracture, however, these regions are not separated because of the lack of inclusions and voids within these regions. Therefore, total separation of the specimen is completed through the “tearing” process by an alternative slip mechanism, while the load drops slowly to zero.
    Stress wave emission was observed during the internal crack formation and propagation. In the latter part of the fracture process, corresponding to the “tearing” process, continuous and increasing emission was observed.
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  • Nobuyuki Mori, Keisaku \={O}gi, Kimio Matsuda
    1976 Volume 40 Issue 4 Pages 406-411
    Published: 1976
    Released: April 04, 2008
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    This study was aimed to elucidate the factors influencing the secondary dendrite-arm spacing of conventionally solidified Al-Cu base alloys. Al-Cu, Al-Cu-Si, Al-Cu-Fe, and Al-Cu-Mn hypoeutectic alloys were quenched during solidification to reveal the secondary arm spacings with various solidification times.
    The secondary arm spacing d(μ) during solidification was expressed as follows: d=22.2θf0.26Vc−0.04910−{0.014Cu(%)+0.022Si(%)+0.03Mn(%)+0.10Fe(%)}, where θf is the solidification time (sec) and Vc is the cooling rate (°C/min). Solute elements decrease the secondary arm spacing in the order of Fe, Mn, Si and Cu under a given solidification condition. This effect could be attributed to the fact that the addition of each element reduced the amount of the primary α-phase. Since d was proportional to Vc−0.05 at any θf, and Vc was also proportional to the square of the degree of supercoolng (ΔT), the dendrite arms would crystallize originally with the size proportional to ΔT−0.1.
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  • Junji Shibata, Hisakazu Kawabata, Sanji Nishimura
    1976 Volume 40 Issue 4 Pages 412-418
    Published: 1976
    Released: April 04, 2008
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    The extraction of MgCl2 was investigated with the mixed ionic extractants consisting of a liquid cationic exchanger and a liquid anionic exchanger diluted with toluene. The extractability, the selectivity for magnesium over sodium and calcium, the efficiency of the recovery process with two-stage extraction and five-stage strip, and the phase separationability were examined for these extractants. On the basis of these results, the most suitable extractant type was selected. The results obtained can be summarised as follows: (1) In the extraction of magnesium from MgCl2 solution the Aliquat 336 system was superior to the Priment JMT system and above all the mixed ionic extractant consisting of Aliquat 336-Versatic Acid 911 had the highest extractability. (2) In the recovery process utilizing a two-stage extraction and a five-stage strip to recover 90% of MgCl2 from 10-fold concentrated sea water, the mixed ionic extractant consisting of Priment JMT-Versatic Acid 911 had the highest concentration of the product and the mixed ionic extractant consisting of Priment JMT-D2EHPA had the smallest volume of organic flow required to produce a given amount of MgCl2. (3) The impurities such as sodium and calcium co-extracted with magnesium into the organic phase could be sufficiently eliminated by scrubbing the extracted organic phase with MgCl2 solution. (4) The Aliquat 336 system had good phase separationability in contact with concentrated sea water, but was emulsified in contact with water. On the other hand, the mixed ionic extractant consisting of Priment JMT-Versatic Acid 911 had good phase separationability in contact with either concentrated sea water or water.
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  • Mitsuo Chigasaki, Kô Soeno
    1976 Volume 40 Issue 4 Pages 419-425
    Published: 1976
    Released: April 04, 2008
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    Precipitation in Fe-32.5 wt%Ni-(2, 4, 5) wt%Ti and Fe-32.5 wt%Ni-(0.24, 0.49, 0.66) wt%Be austenitic steels has been investigated by microscopy and hardness measurement. Besides homogeneous precipitation, cellular precipitation is observed. Cellular precipitation leads to the formation of cells with lamellar morphology and the matrix orientation changes discontinuously across the cell boundary. It is also observed that cellular precipitation becomes remarkable with increasing Ti or Be content.
    Effects of small amounts of additional elements on the cellular precipitation have been investigated. Cellular precipitation is markedly suppressed by small additions of Nb or Zr, though higher aging temperature decreases the effect of these elements rapidly. Recrystallization of cold worked Fe-32.5 wt%Ni austenitic steels containing small amounts of ternary additional elements has also been investigated. It is shown that the elements which raise the recrystallization temperature of the Fe-32.5 wt%Ni austenitic steel have a tendency to suppress the cellular precipitation in the Fe-32.5 wt%Ni austenitic steels containing 2 to 5 wt%Ti or 0.24 to 0.66 wt%Be. The results are discussed from the point of view that the interaction between additional elements and grain boundary is similar to that between additional elements and cell boundary.
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  • Toshio Oishi, Yoshiatsu Sawaragi, Joichiro Moriyama
    1976 Volume 40 Issue 4 Pages 426-431
    Published: 1976
    Released: April 04, 2008
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    Electrochemical measurements have been made of the activity of oxygen in liquid copper alloys with small amounts of cobalt and iron in the temperature range of 1100∼1200°C. The galvanic cell used was
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    Additions of both iron and cobalt lowered markedly the activities of oxygen in liquid copper, and the depression by the addition of iron was about ten times larger than that of cobalt.
    The interaction parameters ε0(Co) and ε0(Fe) were calculated as follows:
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