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Volume 29, Issue 8
Displaying 1-15 of 15 articles from this issue
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Minoru Konuma1965 Volume 29 Issue 8 Pages 743-745
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe changes with time in the elastic constant of copper dilute alloys subjected to cold bending have been measured at room temperature in an attempt to examine the correlation between dislocations caussed by deformation and solute atoms in specimens. The alloy specimens contain less than 1 wt% solute atoms (Sn, Ge, Mg). The experimental results are summarized as follows:
(1) Young’s modulus of specimens subjected to cold bending is increased with time. The variation of Young’s modulus, expressed in terms of the variation of the resonant frequency (Δf), can be given as follows: Δf=a logt, where a is the constant and t is the time after cold bending.
(2) a is decreased with increase of the solue atom content.
(3) a varies with the number of bends.View full abstractDownload PDF (264K) -
Genjiro Mima, Toshihiro Oka1965 Volume 29 Issue 8 Pages 745-750
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSObservation has been made of the behavior of deformation in a narrow region above the grain-boundary during high-temperature shear test along the common grain-boundary, using the high-purity aluminium bicrystal (99.999%) which has the boundary misorientation angle of 36 deg. The high-temperature shear test was carried out in the range of temperatures from 160°C to 300°C. Grain-boundary sliding (shear) was observed to take place without over-all deformation of the component crystal, accompanied by the localized deformation in a region adjacent to the common grain-boundary. Measurements were made of the grain-boundary sliding (shear) as a function of shear stress during the test. From the data, the grain-boundary sliding versus shear stress curves were obtained for a given temperatures, and a plot of the logarithms of the slopes for the curves versus the reciprocal of the shear stress resulted in a series of straight lines. This relationship was discussed by the rate equation. Grain-boundary sliding was found together with zone shear, but not vice versa.
Voids are produced by grain-boundary sliding, and obstructed the grain-boundary migration.View full abstractDownload PDF (929K) -
Shigeaki Sugino, Norihiko Nakanishi, Hiroyasu Mitani1965 Volume 29 Issue 8 Pages 751-756
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of the Mn addition on the phase transformations of β Cu-Al alloys were studied by means of specific heat measurements and X-ray investigations. It was found that two types of martensite, β′ and γ′, were formed in Cu-11.8%Al-4%Mn alloy. Only β′ martensite is observed in a quenched specimen, and both β′ and γ′ martensites are formed in a slowly cooled specimen. In the course of cooling the β phase, the occurrence of an ordering transformation, β→β1, resulted in an alteration in the concentration of the β phase. It is thought that the β′ martensite is formed in the Al-poor β phase and the γ′ in the Al-rich region. Several structures were supposed for the β1 phase which appeared in Cu-Al-Mn alloys.
The crystal structure of the γ′ martensite formed in an alloy containing 12.5%Al and 4%Mn was determined to be orthorhombic with lattice parameters of a=4.45 Å, b=5.30 Å and c=4.24 Å.View full abstractDownload PDF (1312K) -
Sakae Takeuchi, Tsuneo Homma1965 Volume 29 Issue 8 Pages 757-763
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe initiation and growth processes of fatigue cracks were examined microscopically on the specimens of pure metals at the final stage of fatigue. In the specimens under fatigue in air, many voids along the grain boundaries subjected to the repeated sliding were microscopically detected by means of electrolycal or chemical polishing, while in argon atmosphere, these voids were not observed. Macroscopically, fatigue cracks were nearly along the maximum shear stress direction for the specimen in argon atmosphere, while in air they were found in a direction deviated slightly from that mentioned above. The above mechanism is discussed in connection with the effects of air and argon atmospheres experimented.View full abstractDownload PDF (1715K) -
Sakae Takeuchi, Tsuneo Homma1965 Volume 29 Issue 8 Pages 764-770
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to study the mechanism of fatigue at elevated temperatures, the process of fatigue failure under the reversed torsion and bending stresses was observed microscopically on single crystal or polycrystal specimens of pure metals, 99.99%Al and Pb, over the range of temperatures from 0.5 to 0.85 Tm°K in argon or air atmosphere. The results obtained are as follows:
(1) When a single crystal of pure Pb or Al was fatigued under the repeated stress at elevated temperatures, the initiation and growth of subgrains took place, accompanied by a migration of the subgrain boundaries in the maximum shear stress direction of the specimen axis. Their grain boundary faces were aligned nearly orthogonally in argon atmosphere, and along the boundaries slidings of the subgrains occurred with one another and formed cracks. In air atmosphere the alignment of the boundary face in the direction of the maximum shear stress was not complete, resulting in a poor alignment of cracks.
(2) In the case of polycrystals, it was observed that coarse grained specimens showed the same behavior as in the single crystal in the case of a large amplitude of the reversed stress, but under a lower stress the migration of the original grain boundary and the alignment of its face in the directions of the maximum shear stress took the main role in the crack formation as previously reported.
(3) The size of subgrains formed in the fatigue failured single crystal specimen depended appreciably on the testing temperature. Generally, the size became smaller with the decrease of temperature and the prolongation of endurance life.
(4) The relationship between the mechanisms of the fatigue failure at a low temperature and at a high temperature was discussed from the viewpoint of the role of the substructure formed during the fatigue.View full abstractDownload PDF (1198K) -
Sakae Takeuchi, Tsuneo Homma1965 Volume 29 Issue 8 Pages 771-777
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to study the mechanism of fatigue at elevated temperatures, the process of fatigue failure under reversed bending and torsional stresses was observed microscopically on a single crystal and polycrystal specimens of pure metals, 99.99%Al and Pb, over the testing temperatures from 0.5 to 0.85 Tm°K. The results are as follows:
(1) The surface markings consisting of a series of sharp valleys and peaks were observed under the reversed bending stress in the temperature range of about 0.5 Tm°K. The shape of the valleys and hills varied with testing temperatures. The most sharp markings were found in the vicinity of 0.5 Tm°K and these markings became indistinct at temperatures lower and higher than 0.5 Tm°K.
(2) At the critical temperature of 0.5 Tm°K, it was found that the fatigue cracks of the tensile type due to the stress concentration were initiated at the bottom of the sharp valleys, and also that the cracks of the shear type due to the sliding of subgrains as described in a previous report(3) occurred along the boundaries between the markings and the matrices.
(3) It was ascertained that these markings were consisted of unique deformation bands which were developed remarkably by the climbing and alignment of dislocations during repetition of the reversed deformation.View full abstractDownload PDF (1847K) -
Shozo Yoshioka, Yutaka Nakayama, Taichiro Ito1965 Volume 29 Issue 8 Pages 778-781
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe distribution and arrangement of dislocations of Cu-15 at%Al single crystals deformed after various heat treatments were investigated by means of transmission electron microscopy. As the function of annealing temperature, stacking fault energies were determined from the radii of curvatures of extended dislocation nodes with polycrystals and also the yield drops, Δτ, with single crystals were measured. The results obtained are as follows:
(1) The distribution and arrangement of dislocations in the specimen deformed immediately after quenching from 800°C were considerably in order and the distance between the neighboring dislocations in a dislocation array was almost constant. Whereas in those deformed after annealing at 250°C, dislocation pairs and coplanar dislocations were observed.
(2) The yield drop Δτ, at room temperature increased as the annealing temperature increased, reaching a maximum at 250°C for 10 hrs annealing. By annealing over 250°C, Δτ decreased as the annealing temperature increased.
(3) The stacking fault energy showed the same behavior for the annealing temperature as in the case of Δτ.View full abstractDownload PDF (686K) -
Seiichiro Watanabe, Yoshio Kamata, Shinya Chikamatsu1965 Volume 29 Issue 8 Pages 782-787
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor Alnico magnet alloys containing Ti, especially Alnico 7 and Alnico 8 containing 5%Ti, it has been extremely difficult to columnize or coarsen the crystals owing to the reciprocal action between Al and Ti. In view of the fact that Al and Ti are used as an excellent deoxidizer or denitrizer and their gases as fixers in steel, making, the authors considered the neccessity of investigating the effects of N2 and O2 gases which are presumably generated ouring the melting of Alnico magnet alloys containing a large quantity of these two elements. In effect, it was confirmed that the content of N2 gas in other Alnico magnet alloys increased with an increase of the Ti content. It seems that these gases act on Al and Ti, and in the presence of Al, Ti can easily form compounds with these gases; the compounds induces a fine crystallization of Ti containing Alnico magnet alloys. An attempt was made to eliminate the influence of these gases constituently and succeeded in columnizing and coarsening the crystals of the abovementioned magnet alloys by a single or combined addition of one or more elements, not only S but also some elements coherent to S.
The amount of N2 and O2 gases decreased and the columnar crystals became longer as the S content increased.View full abstractDownload PDF (1047K) -
Takuichi Morinaga, Takeo Goto, Tsuneo Takahashi, Iwao Mamiya1965 Volume 29 Issue 8 Pages 787-793
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe transformation of constituent α and β phases during the higher temperature tempering of hypoeutectoid Cu-Be alloys has been studied.
In connection with a selection of the ageing temperature, the eutectoid temperature of the specimen was also investigated. In order to confirm whether a newly accepted eutectoid horizontal of 605°∼608°C is applicable, the specimens were held at 800°C and some of them were isothermally transformed at 600°C, others were quenched and temperd at 575°C up to 620°C, then they were subjected to micrographic and X-ray tests.
The tempering charactristics at 450°, 500°, 550° and 600°C were studied with micrographic and microhardness tests.
The results obtained can be summarized as follows.
(1) The eutectoid horizontal of the system is considered to lie between 605° and 610°C which is nearly equal to Fillnow’s result.
(2) On tempering at temperatures higher than 450°C, the hardening rate in the β phase region is accelerated remarkably as compared with that of the α phase.
(3) The suppressed hardenability in the α phase region by these high temperature ageing is attributed to the direct formation of the equilibrium precipitate γ phase without going thorugh the intermediate γ′ precipitate.
(4) Microscopic observation indicates a rapid growth of pearlitic nodules in both α and β phases, which corresponds to the softening of the specimen.View full abstractDownload PDF (889K) -
Mitsuru Tanino, Tokuhiko Nishida1965 Volume 29 Issue 8 Pages 794-800
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDirect observations were carried out to study the morphology of vanadium carbide V4C3 and the crystallographic orientation relationship between the carbide and matrix in an iron-5% vanadium alloy, containing a small amount of carbon, which was aged at 600°C for various times after quenching from 1200°C into 10% iced brine. The results are as follows: (1) The as-quenched structure consists of simple ferrite and contains a few irregularly distributed dislocations only. Dislocation loops, helical dislocations and precipitates are not present. (2) Large numbers of square or rectangular-shaped thin platelets appear, accompanied by a slight increase in hardness on aging at 600°C. (3) These very thin platelets are identified as vanadium carbide V4C3 containing a small amount of nitrogen by chemical analysis and X-ray diffraction of extracted residues. (4) A definite crystallographic orientation relationship between vanadium carbide and ferrite matrix was determined by analysing a number of electron diffraction patterns as shown in the following: (100)_V4C3 \varparallel(100)_α-Fe, [010]_V4C3 \varparallel[011]_α-Fe, [001]_V4C3 \varparallel[0 \bar11]_α-Fe.View full abstractDownload PDF (1977K) -
Yo Takeuchi, Ken Mochizuki, Masaharu Watanabe, Ichiji Obinata1965 Volume 29 Issue 8 Pages 801-806
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMit Hilfe der Gefügebeobachtung, röntgenographischen Untersuchung, thermischen und chemischen Analysen wurden die Systeme Nickel-Lithium, Nickel-Barium und Nickel-Strontium untersucht. In den Systemen Nickel-Lithium und Nickel-Barium befindet sich keine intermetallische Phase. Die beiden Bestandteile dieser Legierungen sind im flüssigen Zustand nur teilweise mischbar und bilden in einem breiten Konzentrationsbereich eine Mischungslücke. Nickel vermag beispielsweise bei 1200°C bis zu 0.4% Lithium und nur 0.08% Barium zu lösen. Anderseits löst sich Nickel in der Bariumschmelze bei 1200°C bis zu 20.97% und in der Lithiumschmelze bei gleicher Temperatur bis zu 3.47%. Im System Nickel-Strontium tritt eine bisher unbekannte intermetallische Verbindung auf, die sich bei 860°C durch die peritektische Reaktion zwischen den primären Nickel-Kristallen und der Restschmelze bildet. Diese intermetallische Phase, deren Zusammensetzung vermutlich mit NiSr (59.89%Sr, 40.11%Ni) angegeben werden möge, kristallisiert in einer hexagonalen Struktur mit den Gitterkonstanten a=3.332 Å, c=7.009 Å und c⁄a=2.112. Die Phase NiSr und Strontium bilden ein eutektisches System. Der eutektische Punkt liegt bei 92%Sr und 660°C.View full abstractDownload PDF (780K) -
Yo Takeuchi, Ken Mochizuki, Masaharu Watanabe, Ichiji Obinata1965 Volume 29 Issue 8 Pages 806-810
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAuf Grund der Ergebnisse der Gefügebeobachtung, röntgenographischen Untersuchung, thermischen und chemischen Analysen wurde das Zustandsbild des Systems Nickel-Kalzium aufgestellt. Übereinstimmend mit H. Nowotny wurde intermetallische Phase Ni5Ca (12.02%Ca, 87.98%Ni) bestätigt. Ferner ergab sich, dass im System Nickel-Kalzium noch eine bisher unbekannte intermetallische Phase, die vermutlich Ni5Ca2 (21.2%Ca, 78.8%Ni) genannt werden möge, vorhanden ist. Die Phase Ni5Ca2 bildet sich bei 1035°C durch die peritektische Reaktion zwischen den primären Ni5Ca-Kristallen und der Restschmelze. Die beiden intermetallischen Phasen gehören zu einem hexagonalen Kristallsystem mit folgenden Gitterkonstanten: Ni5Ca: a=4.930 Å, c=3.925 Å, c⁄a=0.796; Ni5Ca2: a=5.039 Å, c=10.280 Å, c⁄a=2.040. Im System Nickel-Kalzium treten drei nonvariante Dreiphasengleichgewichte auf. Während die zwei Dreiphasengleichgewichte eutekticher Art (S\ ightleftharpoonsNi+Ni5Ca, S\ ightleftharpoonsNi5Ca2+Ca) sind, handelt es sich beim anderen um ein solches von peritektischer Natur. Der eine eutektische Punkt liegt bei 6%Ca und 1160°C und der andere bei 78%Ca und 605°C. Das peritektische Gleichgewicht erstreckt sich zwischen 12.02 und etwa 33%Ca bei 1035°C.View full abstractDownload PDF (785K) -
Susumu Yoshida, Norio Nagata1965 Volume 29 Issue 8 Pages 811-817
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe dynamic deformation behaviour of annealed polycrystalline aluminium (99.99% purity) has been investigated by a compression test at room temperature using a bar-bar type impulsive loading apparatus. The dynamic stress-strain relation is derived from an analysis of stress-time records at both ends of a cylindrical specimen. The range of strain rates studied is from 1×102 sec−1 to 8×103 sec−1. The results obtained are as follows:
(1) The dynamic stress-strain curve for aluminium is parabolic similarly to the static curve. The dynamic flow stress is always higher than the static one, and the difference between them for the same strain becomes greater with increase of the strain and the strain rate. This shows that the plastic deformation behaviour of annealed aluminium is dependent on the strain rate.
(2) The experimental stress-strain-strain rate relations for annealed polycrystalline aluminium for strain rates ranging from 1×102 sec−1 to 2×103 sec−1 and for strains ranging from 1% to 16% are summarized by a relation, σ (kg/mm^2)=12.8 \dotε^0.38\dotε^1/16 (sec^-1).
(3) When a specimen is dynamically deformed repeatedly at a constant high strain rate, each deformation can be superposed in a similar fashion to the case of static deformation.
(4) The flow stress of a specimen which has been given a certain amount of deformation is different depending on the strain rate history during the deformation. It is higher for a dynamic deformation than for a static deformation. Namely, the flow stress depends not only on the instantaneous strain and strain rate but also on the strain rate history of the specimen.View full abstractDownload PDF (1001K) -
Kaizo Monma, Takeo Sata, Kunio Onodera1965 Volume 29 Issue 8 Pages 817-821
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt was found recently by the writers that the columnar crystal structure of the Alnico alloy can be obtained by zone melting and the crystal orientation method, based on a steep temperature gradient and a low solidification rate. This study was carried out in order to improve zone melting and the crystal orientation method. The results may be summarized as follows:
The temperature gradient at the solid-liquid interface is increased from 100°C/cm to 150°C/cm by water cooling on the solidificated part. The effects of the cooling condition which is shown by the distance between the water surface and the high frequency heating coil and the travelling rate on the macrostructure and magnetic properties have been tested. The exprimental results show that when a suitable water cooling condition is chosen, the macrostructure of Alnico magnet of the columnar crystal structure and parallel to rod axis can be obtained at a travelling rate higher than in the case of air cooling by zone melting and the crystal orientation method.View full abstractDownload PDF (710K) -
Shôtaro Simizu, Kuniyoshi Watai1965 Volume 29 Issue 8 Pages 822-823
Published: 1965
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (159K)
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