Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 53 , Issue 1
Showing 1-23 articles out of 23 articles from the selected issue
  • Toshio Nasu, Kunio Nagaoka, Yoshiyuki Tomitsuka, Hideki Niwa, Isao Aji ...
    1989 Volume 53 Issue 1 Pages 1-7
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The main purpose of this paper is to investigate the crystallization process and the change in mechanical properties with the crystallization of Ni-Zr and Ni-B amorphous alloys. The amorphous specimens, whose compositions were around the eutectic composition, were obtained by a rapid quenching method. The specimens were heated to crystallize up to a temperature of 50 K above Tx for 1.8 ks. The following results were obtained.
    (1) Crystallization temperatures Tx of Ni-Zr and Ni-B amorphous alloys are highest at the composition of the eutectic point, and the activation energies of crystallization are also largest at the eutectic composition.
    (2) The hardness of the specimen in amorphous state was larger than that of mother alloy in the crystalline state. The hardness of the crystallized specimen by heating was larger than that in amorphous state.
    (3) The tensile strength of the specimen in amorphous state was larger than that of crystallized specimen. The specimens in amorphous state were very flexible and tough, but the specimens became brittle with crystallization.
    (4) Young’s moduli of the amorphous specimens obtained by the measurement of bending moment-curvature relation were almost the same as those by other methods. Young’s modulus of the amorphous specimen at the eutectic composition was smaller than those of other compositions, indicating that the Young’s modulus is the smaller for the stable amorphous structure.
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  • Koichi Takemura, Noriyuki Kataoka, Kenji Sumiyama, Yoji Nakamura
    1989 Volume 53 Issue 1 Pages 8-13
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    La1−yFey alloys sputter-deposited on water-cooled substrates have been investigated by X-ray diffraction, magnetization and Mössbauer effect measurements. Although La and Fe are immiscible with each other in the room temperature equilibrium state, the sputter-deposited La1−yFey alloys show a following solubility diagram: a dhcp-fcc mixed phase for y<0.1, a dhcp-fcc-amorphous mixed phase for 0.1<y<0.65, an amorphous phase for 0.65<y<0.83, an amorphous-bcc mixed phase for 0.83<y<0.96 and a bcc phase for y>0.96. The crystallization temperature monotonically increases with increasing y in the single amorphous phase region, while it decreases in the amorphous-bcc phase boundary and shows small concentration dependence in the two phase region. The Fe-rich La1−yFey alloys are ferromagnetic at low temperatures and the saturation magnetic moment of Fe atoms is about 2 μB and nearly constant for y>0.3. On the contrary, it rapidly decreases with decreasing y for y<0.3.
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  • Isao Kawashima, Yasuo Kanzawa, Yoshima Araki, Hiroki Ohno
    1989 Volume 53 Issue 1 Pages 14-19
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The grain boundary reactions in Au-Ag-Pd-Cu alloys containing 0-40 mass% Au were investigated by electrical resistivity measurements, hardness tests, optical microscopic observations, and X-ray diffraction.
    These alloys were quenched from 1073 K and aged at 573, 623, 673, and 773 K. They showed a single phase (fcc) after the solution treatments. The grain boundary reaction after the aging treatments resulted in the formation of the nodule consisting of Ag-rich solid solution, α2 (fcc), and PdCu superlattice, β (CsCl type).
    The main results obtained are as follows.
    (1) Retardation of the grain boundary reaction and increasing of the interlamellar spacing with increasing Au content were considered due to the fact that the nucleation of the nodule is difficult as the aging temperature approaches the phase boundary temperature which becomes lower with increasing Au content.
    (2) Internal strain resulting from continous precipitation become an effective driving force for the nucleation of the nodule because the nodule is also formed in the precipitate free zone.
    (3) The area fraction of the nodule fits to the Johnson-Mehl equation, the nucleation sites of nodule being the edge and plane of the grain boundary.
    (4) The estimated values of activation energy for the nodule formation are 110-170 kJ/mol.
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  • Sadahiro Tsurekawa, Kenta Kuwayama, Hiroaki Kurishita, Hideo Yoshinaga
    1989 Volume 53 Issue 1 Pages 20-27
    Published: 1989
    Released: April 04, 2008
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    In order to clarify the effect of nonstoichiometry on the high-temperature deformation behavior of titanium carbide, single crystals having a wide range of C/Ti atom ratios, x, 0.59 to 0.95, were deformed by compression in a temperature range of 1180∼2270 K and in a strain rate range of 2×10−4∼6×10−3 s−1. It is found that the high-temperature deformation behavior observed is divided into two groups: One is the x-independent or less-dependent type, including the existence of two temperature regions with different deformation mechanisms, the form of mechanical equation at yielding and the work hardening behavior. The other is the x-dependent type, including the yielding behavior, the critical resolved shear stress, τc, the activation energy for deformation and the stress exponent of strain rate, m. In particular at lower C/Ti ratios, most of the behavior in the latter group exhibits a remarkable x-dependence; e.g., around TiC0.75 τc shows a peak and very marked work-softening occurs, whereas at TiC0.59 τc is the lowest and work-softening is less clear.
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  • Hideharu Nakashima, Masami Watase, Hideo Yoshinaga
    1989 Volume 53 Issue 1 Pages 28-33
    Published: 1989
    Released: April 04, 2008
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    In order to clarify the additive effect of different solute elements on the solute-atmosphere drag stress of dislocations, solution-strengthened Al-Mg, Al-Cu and Al-Mg-Cu alloys were creep-tested at 723 K under stresses ranging from 3 to 12 MPa, and the effective stress, internal stress and dislocation-mobility were measured during deformation by the stress-change technique.
    It is found that a relation,
    (This article is not displayable. Please see full text pdf.)
    \ oindentholds in common for these alloys. Here, CMgeq is the equivalent Mg concentration, CMg and CCu the concentrations of Mg and Cu, respectively. From this relation, it is concluded that the effective stress for the solute-atmosphere drag in the tertiary alloys is simply given by the sum of solution hardenings due to Mg and Cu atoms.
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  • Takayuki Takasugi, Tatsuhiko Eguchi, Mitsuhiko Yoshida, Osamu Izumi
    1989 Volume 53 Issue 1 Pages 34-41
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Correlations between the tensile mechanical properties and ordering process have been investigated for Ni3Fe single crystals. Ordering processes were observed by electron microscopy and X-ray diffraction. The ordering process at 743 K observed by electron microscopy showed first the ordered spots of diffraction, then weak contrast of the anti-phase domain (APD), and finally swirllike APD with a size of 50 nm. The critical resolved shear stress (CRSS) first increased gradually, reached a peak, and then decreased to almost a constant value. The increase of CRSS was attributed to the coexistence of the ordered phase matrix and a small amount of the disordered phase. Slip morphology changed from coarse- and band-like to fine as ordering proceeds. Strain hardening in the disordered state was well characterized by well-defined easy glide region and the linear hardening region while that in the fully ordered state showed an exponentially increased hardening rate. It was suggested that the strain hardening in the latter state was due to the interaction between primary slip and microscopically activated secondary slip. Elongation basically did not decrease with proceeding of the ordering but rather increased depending on the tensile orientation of single crystals. Thus, the obtained elongation value depended upon the actually activated primary slip by which the homogeneous deformation was guaranteed regardless of the ordered state or disordered state.
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  • Takayuki Takasugi, Tatsuhiko Eguchi, Mitsuhiko Yoshida, Osamu Izumi
    1989 Volume 53 Issue 1 Pages 42-49
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Correlations between the tensile mechanical properties and ordering processes have been investigated for Ni3Fe polycrystals, containing iron in the range 20-30 at%. The yield stress first increased gradually, reached a peak, and then decreased to a constant value, being similar to the change of yield stress of single crystals. The most rapid change of the yield stress with ordering time occurred in 27.5 at%Fe alloys which had the highest order-disorder transformation temperature. The stoichiometry effect on the yield stress in the disordered state was interpreted by solid solution strengthening of Fe atoms in Ni while that in the ordered state was explained by defect strengthening of the anti-structure. The phenomenon of the discontinuous yielding accompaying Lüders deformation was found in the ordered state. As ordering proceeds, elongation first made a faint plateau and then decreased to a constant value, the level of which was lower than that of an initial (disordered) state. Correspondingly, the reduction in area of alloys decreased and the intergranular fracturing occurred in some areas. It was suggested that the elongation loss of Ni3Fe polycrystals was caused by the decrease of the grain boundary (cohesive) strength due to the change in atomistic structure and bond nature of the grain boundary plane created by ordering.
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  • Norio Matsuda, Keisuke Matsuura
    1989 Volume 53 Issue 1 Pages 50-57
    Published: 1989
    Released: April 04, 2008
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    Creep tests and high temperature tensile tests were carried out on the coarse-grained dispersion-hardened Al-Al2O3-Zr alloy which had an anisotropy of strength due to the recrystallization texture. There types of specimens were used for the tests, each of which had a specimen axis orientation of 0, 45 or 90 degrees against the rolling direction, respectively. Relations between the critical stress for creep deformation and the proof stress were examined.
    The existence of critical stress for creep deformation, σc, was recognized at temperatures from 573 to 773 K. The specimens of 0° orientation had the highest critical stress and creep strength, and the specimens of 90° orientation had the lowest ones. It was shown that the creep deformation could be explained as being controlled by the self-diffusion of Al when it was taken into account that σc decreases with the rise of temperature. The temperature dependence of σc was thought to be due to the interaction between dislocations and impurity atoms which segregated on the interface between dispersed particles and the matrix. Ratios of σc to the 0.1 and 0.01% proof stresses at room temperature, which were thought to be a criterion of the Orowan stress, were in the range from 0.5 to 0.8. Each ratio was nearly constant at the same temperature independent of the axis orientation. The ratio decreased gradually with the rise of temperature, which showed that the interaction between the dislocations and the dispersed particles changes with the rise of temperature.
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  • Kazuo Kasahara, Kenki Hashimoto, Haruo Doi, Tokuzou Tsujimoto
    1989 Volume 53 Issue 1 Pages 58-62
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The oxidation behavior of the intermetallic compounds TiAl containing 34-38 mass%Al has been investigated in a temperature range between 1073 and 1223 K under an atmospheric pressure. The oxidation products have been examined by X-ray diffraction, scanning electron microscopy, and electron probe microanalysis. They are composed of four layers, i.e., TiO2, Al2O3, TiO2+Al2O3 and Ti3Al from the outer side.
    The mass gains during the oxidation obey the parabolic law, which increase rapidly at temperatures above 1073 K. An increase of Al content in TiAl does not change the oxidation resistance but decreases the quantity of spollation of the oxide scales during the cooling. As the oxidation rate of TiAl is lower than that of pure Ti, the existence of the Al2O3 layer have improved the oxidation resistance of TiAl. This Al2O3 layer, however, is not enough dense so as to prevent the oxidation above 1073 K.
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  • Shigeru Ando, Yasuhiro Nakayama, Toshio Shimoo, Hiroshi Kimura
    1989 Volume 53 Issue 1 Pages 63-70
    Published: 1989
    Released: April 04, 2008
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    The behavior or carbon deposition on Fe-Al alloys containing 0-5.7 mass%Al was studied by metallography and thermogravimetry to elucidate the effect of aluminum in iron on carbon deposition on the surface in carburizing gas. Like silicon, aluminum accelerates the deposition of filamentous carbon by promoting the decomposition of Fe3C. In a 20%CO-H2 mixture at 923 K, filamentous carbon deposited with laminar carbon from the early stage of the reaction since the induction period for the filamentous carbon to begin to deposit was shortened by aluminum. This may also cause the retardation of laminar carbon deposition. Therefore, the rate of carbon deposition of the alloys containing 0.8-2.0 mass%Al became smaller than that of iron. In a 10%CH4-H2 mixture at 1273 K, this phenomenon was not observed because of the deposition of filmy carbon instead of laminar carbon. However, carbon deposition on the alloys containing more than 2.7 mass%Al was depressed because Al2O3 formed on the surface. Al2O3 may have formed by the reaction with small amounts of oxidizing gas contained in the atmosphere as an impurity gas. The behavior of Al2O3 formation under the present conditions was discussed thermodynamically and kinetically.
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  • Toshio Shimoo, Tatsuyuki Okamoto, Hiroshi Kimura
    1989 Volume 53 Issue 1 Pages 71-80
    Published: 1989
    Released: April 04, 2008
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    In relation to the smelting reduction of chromite ore, the mechanism of reduction of FeCr2O4 and MgCr2O4 with solid carbon was investigated at high temperatures from 1723 to 1923 K under an argon atmosphere. The rate of reduction was measured by means of thermogravimetry, and the formation of the reduction product was examined by microscopic observation.
    (1) With increase in particle size of FeCr2O4, the reduction rate decreased at low temperatures, but it was scarcely affected at high temperatures. During the reduction of the fine particle of FeCr2O4, the Fe-Cr-C alloy was formed around the graphite particle. In the case of the coarse particle, it was formed in the oxide. FeCr2O4 was essentially reduced by the combination of the gaseous reduction and the formation of Co, and at higher temperatures, the direct reduction by the carbon dissolved in the molten Fe-Cr-C alloy occurred simultaneously. The rate-determining step varied with the particle size of the samples and the experimental temperature.
    (2) When the particle size became extremely small, the reduction of MgCr2O4 was retarded as the result of the variation in the reaction mechanism. In the reduction of the fine particle of MgCr2O4, the graphite particle was coated with carbide. The rate determining step was the solid state diffusion through the cabide. The most of carbide was finely dispersed apart from the graphite particle at a low temperature, 1723 K. The reduction of the coarse particle of MgCr2O4 proceeded topochemically and was controled by the gas diffusion through the porous product layer.
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  • Kazuo Kameda
    1989 Volume 53 Issue 1 Pages 81-87
    Published: 1989
    Released: April 04, 2008
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    The values of E.M.F. of the following cells for liquid antimony-thallium and bismuth-thallium systems have been measured for NTl=0.10∼0.90 over the temperature ranges from 953 to 1230 K and 667 to 1183 K, respectively:
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    \ oindentThe values of E.M.F. obtained for both systems showed a good stability and linear relationships with temperature.
    The activities of both components in these systems demonstrate negative deviations from Raoult’s law over the whole concentration ranges. The activities of both components for the bismuth-thallium system exhibit slightly greater negative deviations than those for the antimony-thallium system, suggesting the moderately larger affinity of thallium for bismuth than that for antimony.
    The α function of thallium for both systems show the curves against NTl, suggesting that these alloys are not considered as regular solutions in either case.
    The maximum values of the heat of mixing are −3.35 kJ/mol for the antimony-thallium system at about NTl=0.65 and −4.69 kJ/mol for the bismuth-thallium system at about NTl=0.61.
    In addition, other thermodynamic functions were calculated on the basis of the results obtained.
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  • Masahiro Ashizuka, Akihiko Murakami
    1989 Volume 53 Issue 1 Pages 88-92
    Published: 1989
    Released: April 04, 2008
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    Elastic moduli, Vickers hardness and fracture toughness of borate glasses containing 33.3 mol% of alkaline metal oxides or alkaline earth metal oxides were studied. Elastic moduli (bulk modulus K, Young’s modulus E, shear modulus G and Poisson’s ratio ν) were related with mean atomic volume V as follows; K=k1Vf, E=k2Vg, G=k3Vh, 1+ν=k4Vj, where f=−1.30 and −1.59, g=−1.64 and −2.13, h=−1.68 and −2.24, and j=0.11 and 0.04 for alkaline metal and alkaline earth metal borate glasses, respectively. The f value obtained from relationship between bulk modulus and mean atomic volume was close to a theoretical value (f=−4⁄3). Vickers hardness HV was correlated with ion-oxygen attraction I. There was a linear relationship between fracture toughness KIC and young’s modulus E.
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  • Masahiro Yamane, Tomihiro Yamaguchi, Kazuichi Mizoguchi, Yukio Suginoh ...
    1989 Volume 53 Issue 1 Pages 93-99
    Published: 1989
    Released: April 04, 2008
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    To investigate the structure of binary silicate in the composition range MeO/SiO2>1, O1s spectra in MeO (MeO=CaO, ZnO)-SiO2 glasses were measured by means of X-ray Photoelectron Spectroscopy (XPS) and quantitative analysis for the existence ratios of silicate anions was carried out by the Trimethylsilylation (TMS) method.
    The results were summarized as follows:
    (1) The measured O1s XPS spectra were fitted precisely by the curve fitting method using the following function with α=0.75. The analyzed value of the oxygen ions (i.e. O0, O, O2−) in crystalline silicate were in good agreement with the theoretical existence ratios of the oxygen ions.
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    (2) Equilibrium constants K for the chemical reaction 2O=O\hat0+O\hat2− in binary silicate, calculated from the analysis of O1s spectra, were 0.0013 in the CaO system and 0.037 in the ZnO system, respectively.
    (3) Polysilicate anions in the composition range of 66.7 to 60 mol% ZnO showed the average polymerization degree of nO0nSi=1.
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  • Yukimi Jyoko, Shiro Haruyama
    1989 Volume 53 Issue 1 Pages 100-105
    Published: 1989
    Released: April 04, 2008
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    Electrodeposition of amorphous cobalt-base alloys has been discussed on the basis of an induced codeposition mechanism. According to the polarization curves measured by stationary or rotating ring-disk electrode technique, it seems to be most plausible that the induced codeposition of amorphous cobalt-base alloys proceeds with the preceding formation of a hydrated complex oxide or a complex hydroxide, such as [CoO·xMoO2·yH2O]ad or [CoOH·nTi(OH)2]ad, as an intermediate. The role of this absorbed intermediate as an inhibitor for the uncleus growth process is of great importance for the occurrence of amorphous phase, together with the high activation overpotential achieved by pulsed current.
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  • Tetsuya Akiyama, Toshio Terasaki, Toshio Enjo
    1989 Volume 53 Issue 1 Pages 106-113
    Published: 1989
    Released: April 04, 2008
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    A nondestructive method has been investigated to predict the time when the degree of sensitization of a welded austenitic stainless steel joint having a plastic strain exceeds a critical degree of sensitization at a low temperature.
    The possibility of determining the plastic strain ratio of the welded joint from its hardness, the relationship between the time and the temperature of the accelerated tests needed for the degree of sensitization of the welded joints to exeed the critical degree of sensitization, and the sensitizations of the welded joints and the laboratory test specimens of the same intergranuler etch ratio and hardness as those of the welded joint were studied.
    The material used in this experimant was type 304 stainless steel plates having a 10 or 30% plastic strain ratio. To measure the degree of sensitization, the EPR test was used. The 10% oxalic acid etch test was used to determine the intergranuler etch ratio.
    From these experimental tests, the following conclusions were obtained. It is possible to determine the plastic strain ratio from the hardness. The relationship between the time and the temperature of the accelerated test needed for the degree of sensitization of the welded joint having a plastic strain to exceed a critical value is linear on the Arenius plots. It is possible to predict the time needed for the degree of sensitization of the welded joint to exceed a critical value by using the laboratory test specimen.
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  • Seiichi Iwata, Nobuo Hara, Nobuyoshi Kobayashi
    1989 Volume 53 Issue 1 Pages 114-118
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    This study was carried out to find various factors affecting the adherence of a chemical-vapor-deposited (CVD) tungsten (W) thin film to the SiO2 substrate. This was done by correlating this adherence with the results of W/SiO2 interface characterization by ESCA (Electron Spectroscopy for Chemical Analysis). The amount of W remaining after the W film was peeled off from the thermally oxidized silicon substrate was taken as a measure of adherence. For interface characterization, W and SiO2 surfaces exposed after the above peeling-off were examined by ESCA. It was found that (1) the adherence of oxidized W to SiO2 is better than that of metallic W to SiO2. Hence, there is a correlation between the amount of oxidized W at the W/SiO2 interface and the W/SiO2 adherence, (2) this adherence is better if there is less fluorine (which comes from WF6 gas used for CVD) at the interface.
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  • Kohji Kawahara, Nobuo Sakuma, Takashi Kimura
    1989 Volume 53 Issue 1 Pages 119-125
    Published: 1989
    Released: April 04, 2008
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    Manganese-based alloys of Mn-Cu, Mn-Cr-Ni, Mn-Cr-Ni-Cu and Mn-Al-Cu systems were examined in connection with the hot- and cold-workability by forging and rolling.
    Addition of copper more than 5 atomic percent improved the cold workability in a variety of the alloy systems used. The most desirable alloying to increase the workability was the simultaneous addition of nickel and copper. Delta-ferritic phase appeared in the systems with chromium, i.e., Mn-Cr-Ni and Mn-Cr-Ni-Cu alloys. The increase in the volume fraction of the phase lowered the workability particularly in the cold rolling, although the volume fraction could be controlled to some extent by heat treatments and modification of alloying compositions. Simultaneous addition of nickel and chromium was superior to a single addition of them for the improvement of the workability.
    It was found that the manganese-based alloys with excellent workability were obtained by the addition of chromium, nikel and copper as well as that of aluminium and copper.
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  • Shigeru Yonetani, Katsuya Imai
    1989 Volume 53 Issue 1 Pages 126-133
    Published: 1989
    Released: April 04, 2008
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    Residual stresses in aluminum bar specimens cold drawn to cross-sectional reductions from 23 to 81% were measured. The preferred orientation of each part in the cross-section on these specimens was measured.
    It was shown that the preferred orientation in each part changed by drawing was closely correlated with the residual stress.
    The effect of the fiber texture on the generation of residual stresses was investigated. A rather high residual shearing stress which was concerned with the normal directional residual stress was produced between the surface and the inner neighboring part under the surface by drawing.
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  • Hitoshi Matsumoto, Ken-ichi Kondo, Akira Sawaoka
    1989 Volume 53 Issue 1 Pages 134-142
    Published: 1989
    Released: April 04, 2008
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    For the analysis of shock compaction of NiTi alloy powder by using a powder gun, the Hugoniot parameters, duration time of shock pressure, and the positions where a plane shock wave collides with an excessive radial shock wave due to the difference in shock impedance between the powder sample and the copper capsule were calculated on the basis of Rankine-Hugoniot equations, the Mie-Grüneisen equation of state and some assumptions. For the flyer velocities of 0.65 to 1.7 km s−1, the Hugoniot parameters were estimated as a function of the flyer velocity and the formulas on the shock duration time in the powder were derived from the propagation behavior of a plane shock wave. The shock duration time calculated numerically by the formulas depends on the depth from the sample head, and the thickness and the flyer velocity. The maximum value of the shock duration time for the present assembly is limited to about 2μs by the rarefaction wave from the capsule side. The positions where two shock waves collide are generally given by three lines on the cross-section of the sample, which approach the sample side with increasing flyer velocity. The region influenced directly by two shock waves, where the shock energy is deposited in excess, corresponded to the large molten band near the circumference of the recovered sample. The melted mass fraction as a thermal effect of the shock compaction was estimated by the shock energy in order to compare with that in the central region of the recovered sample which is compressed up to solid density by a plane shock wave. The generation of cracks and voids in the melt part between powder particles was discussed by considering the shock duration time and the solidification time of the melt part.
    The microstructure changes of the recovered samples are good explainable in terms of present numerical results, and the present method is taken to be effective for the analysis of shock compaction process.
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  • Takafumi Nakayama, Michio Kikuchi, Hakaru Masumoto
    1989 Volume 53 Issue 1 Pages 143-148
    Published: 1989
    Released: April 04, 2008
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    The thermal expansion and magnetization of Mn-22%Ge based ternary alloys containing a element such as Cd or In which belongs to B group in the periodic table were measured in the air-quenching or water-quenching state after homogenizing at 1100 K for 10.8 ks. The crystal structures were compared with those of the basic binary alloy.
    The concentration region of Cd or In in the ternary alloys showing the ε single phase is spread to about 6%, and the area is equal to that of the alloys with Fe. The Néel point TN(ε) shows a slightly higher value than that of the binary alloy. The characteristic thermomagnetic property shown in the binary alloys remains in the ternary alloys. The phase transformation from ε to ε1 can hardly progress in the ternary alloys, too. It means that the ε phase of the ternary alloys once obtained is stable in the vicinity of room temperature. The thermal expansion coefficient of the binary alloys is reduced by additions of Cd or In. It is thought that the concentration showing a minimum coefficient of the thermal expansion shows border of the ε single phase. Cd and In are the elements useful in spreading out the Invar region of the Mn-Ge alloy.
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  • Manabu Tanaka, Michihiro Tagami, Hiroshi Iizuka, Hiroshi Mitobe
    1989 Volume 53 Issue 1 Pages 149-155
    Published: 1989
    Released: April 04, 2008
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    Effects of serrated grain boundaries and cold work on the high-temperature creep-rupture properties of low-carbon cobalt-base superalloy L-605 are investigated at 1089 K and 1311 K.
    Unlike other kinds of superalloys with high-carbon contents, serrated grain boundaries in L-605 alloy are formed by precipitation of tungsten-rich phase during a simple heat treatment. Rupture lives of specimens with serrated grain boundaries are larger than those of specimens with normal straight grain boundaries especially at 1311 K. The rupture ductility is also larger in specimens with serrated grain boundaries at 1311 K, but it is almost the same in both specimens at 1089 K.
    A small amount of cold work up to 10% increases the creep resistance of both specimens at the expense of the creep ductility. The rupture lives are almost unchanged with a small amount of cold work.
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  • 1989 Volume 53 Issue 1 Pages 156
    Published: 1989
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Please see pdf. Wrong:[in Japanese] Right:[in Japanese]
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