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Volume 30, Issue 4
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Yoshio Kamata, Shinya Chikamatsu1966 Volume 30 Issue 4 Pages 313-317
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSColumnization of Alnico 8 magnet alloys containing Ti has recently been accomplished by the addition of a small amount of S. However, little has been known about mechanism. Since Al and Ti tend to form some stable compounds with O2 and N2 gases, it has been predicted that some stable oxides and nitrides to remain in the alloys with large contents of Al and Ti, and that these compounds affect the conditions of the crystal growth. In consequence, the columnization of the alloys is naturally supposed to become possible due to some effect of S on the oxides and nitrides of Al and Ti. In a previous paper, the reduction in the amount of O2 and N2 gases in the alloys with S was described. In this paper, the behavior of S during melting were investigated from the relationship between additional and residual S, and the effects of S on the magnetic properties are also considered. The residual S to decreases rapidly in case of the addtion of more than 0.3 wt% and reduces to 40∼50% after about 5 mins, whereas there is almost no change in the case of the 0.1 wt% addition. The length of the columnar crystals seems to be related to the amount of desulfurization. In the case of more than 0.15 wt% desulfurization, the length of the columnar crystals becomes almost constant, but it has the tendency to shorten considerably by less than 0.15 wt% desulfurization. The optimum residual S for the magnetic properties is known to be 0.15∼0.25 wt%. A falling-off that occurs with less than 0.15 wt% seems to be due to incomplete columnization, and that with more than 0.25 wt% due to the increment of Ti-sulfides. The magnetic properties are 7.1 MGOe in (BH)max in the case of containing the fine crystals near the chillside, while those, in the case of containing no fine crystals are Br: 10,800 G, Hc: 1440 Oe, and 8.0%MGOe in (BH)max.View full abstractDownload PDF (1140K) -
Koichi Nakajima, Junichi Kawamoto, Akio Isogai1966 Volume 30 Issue 4 Pages 317-321
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of wearing or polishing on the microstructure of the surface layer of crystals was investigated on aluminium and various copper alloys by using an X-ray technique and an electron probe microanalyser. A fundamental change in the surface structure in the crystals due to wear was found to be the bending of the lattice planes. The axis of the bending was related closely to the direction of friction on the surface.
The solute composition of the thin layer of the surface in the alloy crystals was observed to increase due to polishing. This phenomenon may be interpreted in terms of the elastic interaction between solute atoms and dislocations during the friction process.View full abstractDownload PDF (1372K) -
Francisco Eiichi Fujita1966 Volume 30 Issue 4 Pages 322-328
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMechanical and thermal stability of crystal lattice imperfections in metallic fine particles were theoretically examined and compared with those in bulk materials. As generally expected, dislocations, grain boundaries and phase boundaries were found to be unstable in fine particles except for a few special cases. The finer the particles, the less stable these imperfections. Because of their very small self-energy, stacking fault layers might be able to survive as the least unstable imperfection after annealing to a considerable extent. In contrast with these imperfections, it is possible to show that vacancies in fine crystal particles could have a thermal equilibrium concentration much higher than that in the bulk crystal at fairly low temperatures. For instance, copper fine particles of 1 micron in diameter could have a thermal equilibrium concentration of vacancies a few hundreds times higher than that in the bulk material at around 300°C, when they have clean spherical surfaces. Application of these calculations to some practical problems, such as the phase transformation, oxidation, and sintering processes of metallic fine particles, were also discussed. The very high thermal equilibrium concentration of vacancies seems to play the main rôle in most of these cases.View full abstractDownload PDF (1292K) -
Kichizo Niwa, Masahiro Shinmei, Ryuzo Shima1966 Volume 30 Issue 4 Pages 329-334
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA kinetic study on the dissolution reaction of alumina into molten carbon-saturated iron was carried out under controlled atmosphere. The increase of the aluminum concentration in molten iron was periodically measured to determine the reaction rate. It was found that the surface condition of crucibles gives significant influence on the reaction rate. An attempt to analyse the mechanism of the reaction was made for the case of some runs that were assured to attain the equilibrium. While the overall reaction can be formulated as Al2O3(s)+3C=2Al+3CO(g), it seems reasonable to assume that the following two interfacial reactions proceed simultaneously, Al2O3(s)=2Al+3O and O+C=CO(g). On this basis, a rate equation of the reaction was derived in which the material transport through the so-called diffusion layers in molten iron was assumed to determine the overall reaction rate. Some of the experimental results could satisfactorily be accounted for by the equation.View full abstractDownload PDF (1943K) -
Shigeo Matsushima1966 Volume 30 Issue 4 Pages 335-339
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh-temperature vacuum tensile-fatigue test (vacuum pressure: 10−5 mmHg, highest testing temperature: 500°C, number of load cycles: 102∼106) for Cu was performed. The relationship between results of the present experiment and high-temperature vacuum tensile-strength (reported at 9th Jap. Cong. Test. Mat., 1965) was discussed. The major results obtained are as follows:
(1) Regardless of the testing temperature and the cyclic load, the minimum deformation rate (dε⁄dN) is expressed by
(This article is not displayable. Please see full text pdf.)
\ oindentwhere \barN is the number of cycles to fracture.
(2) An empirical formula for the relationship among the \barN, testing temperature T (°K) and the cyclic load w can be given by
(This article is not displayable. Please see full text pdf.)
\ oindentwhere \barA=0.308×10−5·K−2, B=10, N0=7×102 and W0=1.91 kg.View full abstractDownload PDF (1209K) -
Toranosuke Komata, Seiichi Mitsumoto, Keizo Kitakaze1966 Volume 30 Issue 4 Pages 340-345
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of lattice defects on the critical current behavior of superconducting Nb in D.C. applied fields have been studied. The concentrations of lattice defects were varied by a various combination of cold work and heat treatment and the changes of these concentrations were estimated by measurements of the electrical resistivity and Vicker’s hardness, and observations by means of electron and optical microscopy.
The disappearance of some point deffects takes place at about 150°C, but no appreciable change in critical current was observed. The disappearance of dislocations in heavily cold worked Nb begins at about 400°C, and the rate of dislocation disappearance becomes smaller at higher temperatures. It was observed by electron microscopy that during annealing at 900°C grain growth took place and in grown-up grains the dislocation density was very low. Comparison of the change in the density of dislocations and grain boundaries with the critical current behavior shows that the dislocations in Nb increase the critical current. From this result the dislocations are considered as the important pinning center of the magnetic flux in Nb.View full abstractDownload PDF (2209K) -
Ichiro Morimoto, Toshiyuki Suzuki, Masayuki Hijikata1966 Volume 30 Issue 4 Pages 346-350
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of alloying elements on the mechanical properties of cold-worked 18Cr-12Ni stainless steel has been examined. Though 18Cr-12Ni stainless steel is soft in a solution treated condition, its hardness and elastic limit increase with increase of cold reduction. Moreover, the low temperature annealing after cold work is effective for increasing the elastic limit. Ferrite-forming elements, molybdenum, tungsten and vanadium, which are substitutionally dissoved, have an effect of improving mechanical properties of the steel, though it is relatively slight in cold work and subsequent annealing condition. Addition of molybdenum is the most effective among these elements. When this steel is annealed at 500°C after 90% reduction, its elastic limit attains 100 kg/mm2. Other mechanical properties of this steel are also improved by the same treatment. That is, the hardness of 500 DPN and tensile strength above 170 kg/mm2 are obtained.
The effect of cold work and subsequent annealing on the γ→α transformation in 18Cr-12Ni stainless steel containing molybdenum, tungsten and vanadium has also been studied. The austenite of this steel containing molybdenum is quite stable and the steel keeps a permeability value of 1.02 at 300 Oe.View full abstractDownload PDF (1094K) -
Masao Homma, Hajime Ichimura, Tadashi Maezawa, Shiro Takasugi1966 Volume 30 Issue 4 Pages 350-356
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is essential for the manufacturing of nodular graphite cast iron that the properties of molten iron before magnesium treatment should be made constant, that is, constant degrees of desulfurization and deoxidation of molten iron, and the minimum magnesium amount should be employed. Though the properties of molten irons of cupola melting are changeable in the begining, intermediate and finishing periods of tapping, respectively, those in the batch system as in an electric furnace can be made constant by the reducing slag refining under a certain formula. On the other hand, the use of cerium together with magnesium enables not only to decrease the amount of magnesium but also to facilitate easy the selection of raw iron materials. From the above standpoint, the authors studied on an industrial scale a manufacturing method of nodular graphite cast iron, which uses the addition of magnesium and cerium to the molten irons desulfurized and deoxidized by the reducing melting in the Heroult electric furnace. Ca-Si-Mg and R-Ca-Si alloys, were used as graphite nodularizing alloys, and the most preferable conditions for theier application were made clear.View full abstractDownload PDF (2361K) -
Masao Homma, Hajime Ichimura, Tadashi Maesawa, Shiro Takasugi1966 Volume 30 Issue 4 Pages 356-360
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe authors have studied the effect of raw iron material, mass effect and residual Mg in the case of manufacturing of the nodular graphite cast iron which uses Mg and rare earth alloys under the most perferable condition previously reported. The results are as follows:
(1) Commercial coke pig irons have a satisfactory graphite nodularizing ability similar to that of the special pig irons for the manufacturing of ductile cast iron.
(2) Compared with the thicker castings, the thinner castings are low in hardness because of their larger graphite areas and greater amounts of ferrite.
(3) By the present method, the castings of 4∼25 mm in thickness have residual Mg amounts of 0.007∼0.025 precent.View full abstractDownload PDF (2162K) -
Hiroshi Miura, Yasuhiro Oouchi1966 Volume 30 Issue 4 Pages 361-366
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSChanges in the microstructure of hypo-eutectoid plain carbon steel by quick thermal cycling below Ac1 were investigated. The specimen of solid bars 6 mm in diameter were subjected to a repetition of rapid heating and cooling in the air under no loads. The period of the thermal cycle was 60 sec and the maximum temperature was 690°C.
The results of obtained were as follows:
(1) Lamellar pearlite was spherodized in the pearlite colony by increasing the thermal cycling.
(2) Very fine spherical cementites were precipitated in the proeutectoid ferrite by the water cooled thermal cycling.
(3) These fine spherical cementites were dispersed in the proeutectoid ferrite and their diameters were about 0.3 micron. The number of the fine spherical cementite was increased by increasing the cooling rate and the thermal cycling.View full abstractDownload PDF (1969K) -
Hisashi Suzuki, Masataka Sugiyama, Takaharu Yamamoto1966 Volume 30 Issue 4 Pages 367-371
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe purpose of this report is to examine some properties of WC-20%Co and WC-5%TaC-20%Co alloys as a function of the carbon content, and to compare their properties with WC-(TaC)-10%Co alloys already reported(1)∼(9).
Two series of alloys, viz., WC-20%Co and WC-5%TaC-20%Co with various carbon contents in the two or three-phase (γ+carbides) range, were prepared by vacuum-sintering at 1375°C for 1 hr. The grain size of carbides in all the alloys was controlled to be approximately the same through some treatments before sintering.
The main results are as follows:
(1) A maximum value of the transverse-rupture strength is obtained at the low carbon alloys in the two or three-phase range. However, in the case of 10% alloys, the maximum value is at the high carbon alloys. (2) The addition of TaC up to 5% does not decrease the transverse-rupture strength, but the 3%TaC addition to 10%Co alloys decreases its value. (3) The width of the two or three-phase range is approximately two times as wide as that of 10%Co alloys. (4) The TaC addition increases the hardness but decreases the density. (5) The γ-phase contains almost no TaC. (6) The aging phenomena accompanied by the Co3W type precipitation is also ascertained in these alloys, but there is the difference that the hardness and the coercive force of these alloys increase after aging.View full abstractDownload PDF (1590K) -
Kazuo Tsuya1966 Volume 30 Issue 4 Pages 372-376
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relation between the ductile-brittle transition behavior and the specimen direction was investigated with beryllium sheet. Most of the basal planes of beryllim sheets used in this experiment were parallel to the rolling direction. But in the transverse direction there was a concentration of the basal poles at 25 degrees from the normal to the sheet. Two kinds of tensile test pieces, i.e. longitudinal and transverse specimens, were cut from the sheet. The tensile ductility of the longitudinal specimens was compared with that of the transverse specimens in the temperature range of 100°∼400°C.
The results obtained are as follows:
(1) Beryllium sheets were inferior in tensile ductility in the transverse direction to those in the longitudinal direction in the temperature range of 100°∼400°C. Furthermore, it was found that the shape of transverse tensile test curve was quite different from that of the longitudinal test curve.
(2) The effects of precipitation treatment and grain refinement on the tensile ductility were examined. Aging at 700°C for 120 hrs increased the transverse ductility at 400°C, though it was not observed below 300°C. On the other hand, the grain refinement from 180 μ to 40 μ increased the ductility of the transverse specimens at 300° and 400°C. Besides, the anomalous shape of the transverse tensile test curve was remarkably changed by the grain refinement.
(3) In the temperature range of 100°∼300°C, the tensile ductility decreased with the increasing rate of loading, while the ductility at 400°C did not vary or increased with the loading rate.View full abstractDownload PDF (1280K) -
Akio Yamaguchi, Haruhiko Iinuma, Jioichiro Moriyama1966 Volume 30 Issue 4 Pages 377-382
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe hydrogen reduction of ilmenite ore (Ceylon and Australian) was investigated over the temperature range of 650° to 800°C by means of thermobalance, X-ray diffraction patterns and the X-ray micro-analyser. The reduction rate can be described by the following equation: −d(1−x)⁄dt=k(1−x)1−n, where x is the fraction of reduction at time t, k is the rate constant and 1−n is the constant corresponding to the reaction order. The overall reduction is found to consist of two stages as a result that the linear relationship between log−d(1−x)⁄dt and log(1−x) is yielded in the 1st and 2nd stage, respectively. The apparent activation energy for reduction of Ceylon ore was 20.8 kcal/mol in the 1st stage and 28.3 kcal/mol in the 2nd stage. This indicates that the 1st stage differs in the objects of reduction from the 2nd stage. X-ray powder patterns of the sample partially reduced at 750°C failed to reveal the above kinetics, but the oxygen concentration profiles obtained semi-quantitatively by means of the X-ray micro-analyser show the existence of intermediate oxides, and the multiple phase layer structure is presumed in the ore particle. From the results of investigation, it seemed reasonable to assume that the reduction proceeds through the process consisting of the following two stages:
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Koji Shibata, Shotaro Morozumi, Shigeyasu Koda1966 Volume 30 Issue 4 Pages 382-388
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDiffusion couples of aluminium and iron were held in vacuum at 605°∼655°C up to 96 hr. The section crossing through the alloy layer formed between two metals was examined with an optical microscope, a micro-hardness tester, and an electron probe X-ray microanalyser. The results obtained are as follows: (1) The greater part of the alloy layer was the compound of Fe2Al5. (2) The diffusion of aluminium into iron matrix and iron into aluminium matrix was so little that it could not be estimated. (3) The activation energy of diffusion in the growth of the alloy layer was estimated to be 54 kcal/mol. (4) Finally some considerations on the mechanism of the formation and growth of the alloy layer have been made.View full abstractDownload PDF (1736K) -
Shotaro Morozumi, Shoji Goto, Michio Kikuchi, Shigeyasu Koda1966 Volume 30 Issue 4 Pages 388-394
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInteraction between dislocations and oxide particles was observed with a transmission electron microscope. The specimens of aluminium and magnesium were prepared so that an array of oxide particles was introduced in the middle part of each specimen along the direction of the final rolling. After heat-treatment or heat-treatment and working, the specimens were thinned by electrolytic polishing and were set in an electron microscope. As the dislocations were moved by the emission of electron beam, microphotographs were taken intermittently.
The results obtained are as follows:
(1) Rapid cooling from annealing temperature resulted in the formation of small dislocation loops in aluminium matrix. There were, however, denuded zones of these loops in the vicinity of the array of particles as well as grain boundaries. There relatively long dislocations associated with particles were observed. In the case of magnesium specimens, the generation of dislocations from the interface of matrix and particles and consequently the formation of dislocation networks were observed. (2) Many dislocations in both specimens which were generated and moved by emission of electron beam, interacted with particles. In aluminium specimens, arrests of moving dislocations and cross slips were preferentially observed. In magnesium specimens, however, the formation of dislocation loops as well as arrest and bending of dislocations was observed. (3) According to the working degree, cell structures, especially in aluminium, were formed, an array of particles taking part in its formation. However, with increase in working degree there were no appreciable differences in the cell structures between the matrix and the vicinity of the array of particles. (4) Finally, some considerations were made on the decrease in critical shear stress required for dislocation to pass through particles dispersed non-uniformly.View full abstractDownload PDF (1506K) -
Akira Adachi, Yoshikiyo Ogino1966 Volume 30 Issue 4 Pages 394-399
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOn aluminium killed Ni-Cr-Mo case hardening steel, the austenite grain size and it’s coarsening behavior were studied in relation to the aluminium nitride precipitate observed by electron microscopy. The main results are as follows: (1) If the original structure before the austenization is same, the initial austenite grain size becomes smaller as the aluminium nitride precipitate becomes finer, in accordance with Zener’s experession. (2) When the size of the aluminium nitride precipitate is smaller than a certain degree, the discontinuous coarsening of austenite grains occurs at the temperature at which the precipitate dissolves in the matrix or aggregates to a larger size, but when larger than that, the apparently continuous or discontinuous coasening occur depending on the prior heat treatment at much lower temperatures.View full abstractDownload PDF (2826K) -
Zenzo Henmi, Takeshi Nagai1966 Volume 30 Issue 4 Pages 400-406
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSince the Cu-Be alloy has high age-hardenability, many investigations have been carried out on the characteristic. In this study the Cu-2 wt%Be alloy was aged at a different temperature and its mechanism of precipitation was studied by means of hardness measurement, optical microscopy and transmission electron microscopy. The results show that the aging sequence of the Cu-2%Be alloy in the grains is α→G.P. zone→short range order→γ and that at the grain boundary α→γ. The precipitated γ phase is very fine and coexist with fine α grains as a mixture. The high age-hardenability of the Cu-Be alloy seems to be caused by the formation of the G.P. zone and the short range order inside the grains.View full abstractDownload PDF (1442K) -
Hifumi Hotta, Yoshiroh Iwama1966 Volume 30 Issue 4 Pages 406-411
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInternal friction has been measured at elevated temperatures to study the diffusion of C atoms in low carbon Fe-Al-C alloys containing 0.002∼5.28 wt%Al. It is observed that the Snoek peak proper to the Fe-C binary alloys is broadened and reduced in height with increasing of the Al content. Besides, the addition of Al produces another peak at the higher temperature, and the peak increases in height at the expense of the Snoek peak. The activation energies of the Snoek peak and the second peak are 18.5∼19.5 kcal/mol and 23.6∼24.5 kcal/mol, respectively. Though the Snoek peak in pure Fe-C alloy is somewhat greater in width than that calcuated as having the single relaxation time, the Snoek peak in the Fe-Al-C alloys are still larger in width than that of the binary alloy and the second peak is much greater in width. The broadening can be explained by allowing their relaxation times to have an appropriate error-functional distribution. By selecting suitable values of parameters, the calculated curves are fitted very well to the observed ones.
From the obtained results, it is suggested that the Snoek peak is due to the stress-induced diffusion of C atoms at Fe-Fe interstices expanded by the addition of Al, and the second peak is due to that at Fe-Al interstices. The Fe-Al interstices are considered as if they were under a compressed condition, as contrasted with the Fe-Fe interstices.View full abstractDownload PDF (1890K) -
Seita Sakui, Tsutomu Mori, Kimiko Sato1966 Volume 30 Issue 4 Pages 412-413
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (413K) -
1966 Volume 30 Issue 4 Pages 413
Published: 1966
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:[Please see pdf], [in Japanese] Right:[Please see pdf], [in Japanese]View full abstractDownload PDF (71K)
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