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Volume 49, Issue 6
Displaying 1-15 of 15 articles from this issue
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Void Swelling and Microstructural Change of Type 316 Stainless Steel by Irradiation in Fast ReactorsMasahiko Itoh, Shouji Onose1985 Volume 49 Issue 6 Pages 389-396
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSVoid swelling and microstructural change during irradiation were investigated for Type 316 stainless steels different in the fabrication process and/or the phosphorus content. The relation between Ni content and swelling was also examined. The irradiations were performed in the Japan Experimental Fast Reactor JOYO, the French fast reactor Phenix, etc.
The irradiated specimens were examined by a scanning transmission electron microscope equipped with an energy dispersive X-ray analyser. Results obtaind are summarized as follows.
(1) Phosphorus in the steel was found to be effective as a swelling inhibitor.
(2) Cold work reduced the swelling of the steel.
(3) The segregation of Ni to grainboundaries, precipitates and surroundings of voids decreased the Ni content in the austenite matrix.
(4) With increaseing swelling, the initial Ni content of 13% decreased to approximately 9%Ni in the austenite matrix.View full abstractDownload PDF (3117K) -
Yoshihiro Takahara, Takashi Okabe, Hidehiko Matsuda1985 Volume 49 Issue 6 Pages 397-401
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe structural relaxation of an amorphous Fe79B16Si5 alloy was studied through electrical resistivity measurements. The alloy obtained by rapid quenching relaxes to a certain structure during isothermal annealing at temperatures below crystallization temperature, Tx=778 K. The structure was rather stable under the experimental condition adopted here. The irreversible decrease of resistivity and increase of its temperature coefficient were observed during the structural relaxation. These changes can be caused by the changes in topological short range order (TSRO) that involves the elimination and redistribution of quenched-in excess free volume. For the specimen pre-annealed at 673 K for 10.8 ks, reversible changes in resistivity was observed during the continuous heat cycles consisting of heating at the rate of 0.083 K/s and air cooling between 299 K and 673 K.View full abstractDownload PDF (771K) -
Kazuo Nagata, Hiromitsu Ino1985 Volume 49 Issue 6 Pages 402-410
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe structure and aging behavior of melt-spun Fe-5-20 at%B were studied by Mössbauer spectroscopy, X-ray diffraction and differential scanning calorimetry. Amorphous phases were obtained in the specimens of 12-20 at%B. The bulk fcc γ phase was observed in the 10 at%B alloy, together with the bcc α and orthorhombic Fe3B phases.
The γ phase was also observed at the free and roll side surface of the amorphous foil specimens containing 13 or 12 at%B. The surface α phase was formed in the 12 at%B specimen depending on the cooling condition. The γ or α phase formed at the surface has a strong texture so that the close packed plane ((111)γ or (110)α) is parallel to the surface of the amorphous specimen in order to minimize the surface free energy.
The 12, 13 and 15 at% alloys showed two steps of crystallization, amor.→bcc α+amor.→bcc α+tet. Fe3B. A single α phase region suggested by Takahashi et al. was not observed.
Mössbauer absorption sub-peaks with a hyperfine magnetic field of 24.2 MA/m (0.92 of the value for α-Fe) were clearly observed in the as-quenched 5 and 10 at%B and crystallized 13 at%B specimens. The peaks indicated the existence of an iron atom interacting with one neighboring boron atom probably dissolved in the α phase. The change in the lattice constant suggests that most of the B atoms occupy the substitutional atom positions.View full abstractDownload PDF (1386K) -
Kenki Hashimoto, Haruo Doi, Tokuzou Tsujimoto1985 Volume 49 Issue 6 Pages 410-416
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStructures of Ti-Al-V alloys have been examined by means of electron probe microanalysis and X-ray diffractometry after being annealed for 2.68 Ms at 1073 K or for 691 ks at 1273 K.
Two three-phase equilibriums, Al8V5+(V, Ti)Al3+(V) and Ti3Al+(β-Ti)+TiAl, have been found, and isothermal diagrams at 1073 K and 1273 K have been reconstructed.
The titanium content in Al8V5 phase is about 5 mass% at 1273 K and 1 mass% at 1073 K. In the TiAl compound which contains vanadium up to the solubility limit, the axial ratio c/a varies from 1.012 to 1.050 with increasing aluminium content.View full abstractDownload PDF (1398K) -
Yukio Inokuti, Chizuko Maeda, Tomoo Tanaka1985 Volume 49 Issue 6 Pages 417-422
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn an attempt to elucidate the mechanism for the inheritance of (110)[001] grains from the original hot-rolled texture, a hot-rolled sheet of the high induction and low core loss grain oriented silicon steel containing MnSe, Sb and Mo as inhibitors has been used with ground both sides of two strong (110)[001] textures in the vicinity of surface of hot-rolled sheet (ground sample) or without ground both sides (no grinding sample). The secondary recrystallization has been caused by a two-stage cold rolling process with an intermediate annealing.
Results obtained are described as follows.
(1) In the ground sample the secondary grains develop, but the orientations of secondary grains deviate up to 0.35 rad from (110) plane and 0.44 rad from ideal (110)[001] orientation.
(2) Perfection of secondary grains in the ground sample is exceedingly worse than that in the sample without grinding, in which an average deviation of [001] axis of the secondary grains is no more than 5 degrees from the rolling direction.
(3) The average diameter of secondary grains in the ground sample is approximately two times as large as that in the sample without grinding.
(4) The preferred orientation of texture in the vicinity of surface of the ground sample after an intermediate annealing and as-decarburized and primary recrystallized annealing is weak {hk0}·⟨001⟩ component.
(5) It is believed that the formation of strong (110)[001] texture in the vicinity of surface of hot-rolled steel is indispensable for developing the celebrated (110)[001] secondary grains.View full abstractDownload PDF (1253K) -
Hideyuki Ikeda, Hidehiko Matsuda1985 Volume 49 Issue 6 Pages 423-430
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSChanges in electrical resistivities of Al-4.5 at%Zn alloys in an initial stage of aging were measured and compared with results obtained from simulation experiments. There was a qualitative agreement in both results. Then the rate equation of growth of G.P.zones based on the vacancy pump model derived by Girifalo and Herman was examined with the simulation experiments, and its validity was confirmed. Furthermore, the scaling laws for size distributions of clusters of solute atoms and the structure functions for the spatial configurations of the solute atoms in Al-Zn alloys were also satisfied in the simulation experiments.View full abstractDownload PDF (1056K) -
Masashi Arita, Saburo Nasu, Francisco E. Fujita1985 Volume 49 Issue 6 Pages 431-438
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe site population analysis of iron atoms in Fe3Si alloys wtih D03 superlattice structure was performed in the 57Fe Mössbauer spectroscopy for crushed and annealed powder specimens with silicon concentrations of 23.3 at% and 25.5 at%. The obtained Mössbauer spectra were analyzed as superpositions of at least three six-line components. Relative intensity for each component has been analyzed using thin foil approximation. The atomic configuration, the relative number of iron atoms of the component and, therefore, the short-range-order parameter were determined from the values of hyperfine field and relative intensity for each component.
In order to determine the long-range-order parameters of the alloys, the procedure having two steps was performed: At first, the perfectly ordered D03 lattice of 25 at%Si was constructed by computer simulation, and then atoms were replaced randomly to reach any desired value of the alloy concentration and of the degree of order. By comparing the simulation with the result of Mössbauer experiment, the long-range-order parameters, S(D03) and S(B2), were determined. The values agreed well with those obtained by the powder X-ray diffraction technique.View full abstractDownload PDF (1121K) -
Tsunehiko Todoroki1985 Volume 49 Issue 6 Pages 439-444
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA shape-memory alloy, which has a one-way memory, can become a two-way memory, when it is combined with a bias load. The effects of the bias load and heat treatment temperature on the deflection-temperature (δ-T) loop of the two-way memory of a Ti-50.2 at%Ni alloy coil spring have been studied, and in addition, the relation between the δ-T loop and the phase transformations for three phases of CsCl(B2) type, rhombohedral (R) one and monoclinic (M) one in the alloy has been investigated by D.S.C. and electrical resistance measurements.
The results are summarized as follows:
(1) The temperature hysteresis and the bias load (being replaced by shear stress) dependence of the transformation temperature are both larger for B2\ ightleftarrowsM or R\ ightleftarrowsM than for B2\ ightleftarrowsR transformations. The maximum shear stress in the R-phase existent region in the temperature-shear stress coordinates is, therefore, larger during cooling than during heating. Furthermore, the maximum shear strses in the R-phase existent region decreases with increasing heat treatment temperature, and the R-phase scarcely exists, when the alloy is heat-treated above ca. 800 K.
(2) The phase transformations are divided into three according to the phase diagrams in the temperature-shear stress coordinates and in the temperature-heat treatment temperature coordinates.
(a) The R-phase does not exist during either cooling or heating. (Ms<As, the alloy of higher shear stress applied or higher heat treatment temperature); B2→M during cooling and M→B2 during heating.
(b) The R-phase exists only during cooling. (Ms<Ms′<As); B2→R→M during cooling, and M→B2 during heating from M, or R→B2 during heating from R.
(c) The R-phase exists both during cooling and heating. (Ms<As<Ms′, the alloy of lower heat treatment temperature and lower shear stress applied); B2→R→M during cooling, and M→R→B2 during heating from M, or R→B2 during heating from R.View full abstractDownload PDF (913K) -
Hidenori Kohzuki, Toshihiko Akiyama, Sachio Oki1985 Volume 49 Issue 6 Pages 445-450
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSintered Cr steels containing 1 and 3 mass%Cr were prepared from mixtures of atomized Fe-Cr alloy powder and graphite powder, by compacting and sintering at 1523 K for 3.6 ks in vacuum. Specimens were nitrided at 773 K for 3.6 ks in an ammonia gas atmosphere.
The properties of the nitrided layer were investigated by electron probe microanalysis, transmission electron microscopy, X-ray diffraction and microvickers hardness testing etc, and the wear characteristics were studied by Ohgoshi type micro-wear testing without lubricant.
Results obtained are summarized as follows.
(1) Compound layers were formed not only on the surface but on the inner surface of pores and at grain boundaries connecting with pores. It was found by X-ray diffraction that these compounds were ε-Fe2.3N phases.
(2) Fine precipitates were observed in the diffusion zones of sintered 1 and 3 mass%Cr steels by transmission electron microscopy, and were identified with CrN particles by electron diffraction.
(3) By nitriding, the wear resistance of the sintered Cr steel was improved remarkably. But the wear resistance was aggravated by spalling of the compound layer formed on the surface, therefore, it is desirable to remove the surface compound layer, in order to have the good wear resistance.
(4) In case of removing the surface compound layer, the wear rate of the nitrided specimen of the sintered 1 mass%Cr steel was nearly equivalent to that of the sintered 3 mass%Cr steel, so it is considered that the Cr content of the sintered Cr steel for nitriding with an ammonia gas must be about 1 mass%.View full abstractDownload PDF (1414K) -
Yoshio Anekawa, Toshihiko Koseki, Toyonobu Yoshida, Kazuo Akashi1985 Volume 49 Issue 6 Pages 451-456
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe co-condensation process of high temperature metallic vapors was examined, in order to investigate the nucleation and growth phenomena of binary high temperature metallic vapors as well as the possibility of synthesizing ultrafine alloy particles from a vapor state. Experimental investigations were made on the Nb-Si and V-Si systems by using an rf plasma evaporation method. The binary composition controlled metallic vapors generated in a plasma flame were quenched at the cooling rate of about 105 K/s and deposited on a water-cooled sphere. X-ray diffraction analysis revealed the presence of all the intermetallic compounds expected by each phase diagram. Especially, in the case of V-Si system, composition controlled alloy particles with the size range from 20 to 100 nm could be prepared successfully. On the other hand, in the case of Nb-Si system, the powder of a single phase could not be obtained, though the particle size ranged from 10 to 20 nm and the identified phases roughly corresponded to the expected phases. Theoretical investigations were also undertaken to elucidate the mechanism of the process. According to these investigations, in order to overcome widely different vapor pressure ratios as in the case of Nb-Si system and to control desirably alloy compositions, the time and space required for the nucleation of each element must be highly restricted to a common period and region by using more rapid quenching rate than that can be attained in this study.View full abstractDownload PDF (1087K) -
Shinya Otsuka, Hitoshi Horiuchi, Zensaku Kozuka1985 Volume 49 Issue 6 Pages 457-462
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs part of a program of study of the thermodynamic behavior of oxygen dissolved in binary melts including bismuth or antimony (Group Vb), the activity coefficient of oxygen, γO, in liquid Sb-Sn alloys at 1073 and 1273 K has been measured over the entire composition range. A modified coulometric titration method with the electrochemical cell: O in liquid Sb-Sn alloys/ZrO2(+CaO)/air, Pt, was used. The measured lnγO values at both temperatures, plotted against alloy composition, lie on upwardly concave curves and show large negative deviations from those predicted by Jacob and Alcock’s quasi-chemical model. This behavior appears to be in line with previous observations in Bi-In-O, Bi-Pb-O, Bi-Sb-O, Cu-Sb-O, In-Sb-O and Pb-Sb-O systems. The enthalpy and entropy values for oxygen dissolution in Sb-Sn alloys, plotted against alloy composition, also exhibit upwardly concave curves.View full abstractDownload PDF (687K) -
Katsuyuki Takahashi, Takayuki Yoshioka, Yoshisuke Nakamura, Haruno Oko ...1985 Volume 49 Issue 6 Pages 463-468
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe direct analysis of solid metal samples by inductively coupled plasma emission spectrometry has been investigated. An aerosol generator (AG) by low voltage spark discharge was used for vaporization of metal samples, and the aerosol was introduced into plasma through an aerosol cyclone. The effect of the length of a transporting tube (stainless steel) was examined. The lengths investigated were 1, 3, 5, 7.5 and 10 m. The spectral intensities lowered, the amounts of aerosol transferred into plasma decreased, and the relative standard deviation of spectral intensities became worse with the increase of the length. In the determination of Co, Cr and V, no phenomenon of selective adhesion to the inner surface of a transporting tube was observed. In the case of tungsten, there were a selective adhesion to the inner surface of the tube and a selective removal in the aerosol cyclone. However, in the practical analysis there was no problem, since the standard samples for calibration were affected in a similar way as the samples for analysis. This method was compared with the vacuum quantometer analysis. In the present method, there was no interfering elements, while in the latter several major elements showed spectral interferences, and in the calibration curves for V and W, there were some standard samples which did not fit the calibration curves. The direct ICP emission spectral method gave excellent straight calibration lines for all the elements such as Mo, W, Co, Si, Mn, Cr, V and Cu under investigation, and showed better accuracy and precision.View full abstractDownload PDF (1048K) -
Takayuki Yoshioka, Hitoshi Yamaguchi, Haruno Okochi, Emiko Sudo1985 Volume 49 Issue 6 Pages 469-475
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe determination of oxygen in zirconium, titanium and their alloys by the impulse furnace fusion method has been investigated. The optimum analytical conditions were examined using four kinds of metal baths namely, nickel, platinum, nickel and tin, or iron and tin. The comparison among analytical values by different metal baths and different methods has been made. In the case of the flux method in which a sample and nickel or platinum ten times as much as the sample were put into a crucible simultaneously, the analytical values of both flux methods agreed well with each other, when titanium samples were analysed at ca. 2800 K. However, in the analysis of zirconium, the analytical values by the platinum flux method were lower than those by the nickel flux method, although addition of a suitable amount of tin made both flux methods give consistent analytical results. In the case of the metal bath method in which bath metals were put into a crucible and degassed just before the analysis of a sample, the optimum contents of tin in the baths were 25-35% for the nickel-tin bath and 40-50% for the iron-tin bath. The temperature ranges suitable for the determination of oxygen were ca. 2300-2800 K for the former bath and ca. 2400-2900 K for the latter one. The analytical values of oxygen in zirconium and titanium by both metal bath methods agreed well with those by the two flux methods. The analytical results of oxygen in zirconium and titanium alloys by the flux and bath methods were satisfactory.View full abstractDownload PDF (1349K) -
Akira Sawamoto, Keisaku \={O}gi, Kimio Matsuda1985 Volume 49 Issue 6 Pages 475-482
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe freezing processes and solidification structures of Fe-5%Cr and Fe-15%Cr alloys with 0.5 to 4.7%C and 0 to 7.5%Nb were investigated metallographically. The distribution of alloying elements were also studied by use of E.P.M.A. to clarify the behavior of elements during solidification. The constitutional diagrams for liquidus surfaces of Fe-5%Cr-base alloys and Fe-15%Cr-base alloys were established. In the 5%Cr system primary δ, γ, NbC and M3C phases and eutectic reactions of Liquid→(γ+NbC), Liquid→(γ+M3C) and Liquid→(γ+NbC+M3C) appeared. Primary δ, γ, NbC and M7C3 phases and eutectic reactions of Liquid→(γ+NbC), Liquid→(γ+M7C3) and Liquid→(γ+NbC+M7C3) occurred in the 15%Cr system. Primary niobium carbides grew dendritically and eutectic niobium carbides crystallized in the shape of petal. The amount of NbC increased and that of M3C and M7C3 decreased with increasing niobium content of alloy. During solidification niobium was preferentially partitioned to primary and eutectic NbC, and chromium to M7C3 crystals. The partition ratios of niobium and chromium to primary γ were 0.02 to 0.01 and 0.93 to 0.72, respectively. They decreased with the increase in the carbon content of alloy. The addition of 0.3%Ti to the melt nodularized both primary and eutectic niobium carbides, because many tiny titanium carbide particles precipitated at higher temperatures nucleated the niobium carbides.View full abstractDownload PDF (2299K) -
Kenji Miwa, George Yoshinari, Teruo Ohashi1985 Volume 49 Issue 6 Pages 483-489
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOff-eutectic Al-5 mass%Ni alloys have been stirred rotationally at the rates of 0.83 s−1 to 12.5 s−1 in a partially solidified state, and variation of eutectic structures has been studied. Furthermore, Al-Al3Ni eutectic alloys have been solidified unidirectionally with stirring, and the effect of stirring on the growth morphology of the solidification front has been discussed. Component phases in the Al-Al3Ni eutectic are separated by stirring in a partially solidified state. Al-5 mass%Ni alloys decrease in the apparent viscosity temporarily in the beginning of the eutectic reaction at a given rotational speed. By stirring, the leading phase of the eutectic, Al3Ni, grows coarser, branches occasionally and then protrudes from the solidification front into the liquid. Together with this phenomenon, and α dendritic phase is formed in the solidification front.View full abstractDownload PDF (2538K)
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