巻号一覧
54 巻, 9 号
選択された号の論文の13件中1～13を表示しています
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坂田 孝夫, 森 博太郎, 藤田 広志, 鈴木 彰1990 年 54 巻 9 号 p. 955-961
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe electron-irradiation-induced crystalline-to-amorphous (C-A) transition in β-SiC and the crystallization of the irradiation-produced amorphous SiC upon annealing have been studied by a combination of ultrahigh voltage electron microscopy and high resolution electron microscopy. β-SiC can be rendered amorphous by 2 MeV electron irradiation. The total dose of electrons required for the C-A transition at 170 K is approximately 1.2×1026 m−2. The irradiation-produced amorphous SiC crystallizes into β-SiC at 1233±10 K. Namely, at this temperature, crystallites of β-SiC with random orientation, ranging from a few nm to ten and a few nm in diameter, appear in the amorphous matrix. with increasing annealing temperature, the crystallites make grain growth. In the crystallites a high density of stacking faults have been introduced on the (111) plane.抄録全体を表示PDF形式でダウンロード (5668K) -
吉見 享祐, 村山 洋之介, 花田 修治, 石山 成志1990 年 54 巻 9 号 p. 962-969
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーOrientation and grain boundary character distributions in recrystallized pure titanium with hcp structure were investigated by means of the Selected Area Channeling Pattern (SACP) method in order to understand the formation of a characteristic recrystallization texture in pure titanium. The samples uni-directionally rolled at room temperature with reduction of about 95% were annealed at 1073 K for 600 s and 7.2 ks in vacuum, respectively. Texture evolution was measured both with X-ray diffraction and with the SACP method which was developed quite recently by the present authors. By analyzing the SACPs orientation relationship between the adjacent grains was calculated and the grain boundary character was determined on the basis of the Coincidence Site Lattice model. The distribution of grain boundary disorientations was bimodal; i.e. two peaks at low (about 15°) and high (65-70°) disorientation. Moreover, there was a tendency that low angle boundaries form clusters and the orientation distribution is inhomogeneous in relation to microstructure. The fraction of coincidence boundaries about ⟨10\bar10⟩ or ⟨11\bar20⟩ was very low in the samples annealed for 600 s and 7.2 ks, while the Σ7 coincidence boundaries about the ⟨0001⟩ axis increased with annealing time.抄録全体を表示PDF形式でダウンロード (1266K) -
相原 智康, 青木 清, 増本 健1990 年 54 巻 9 号 p. 970-975
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーAmorphous single phases were isothermally formed by hydrogenation of the C15 Laves compounds RNi2 (R=Sm, Gd, Dy, Ho, Er) at 400 K and 5.0 MPa H2 for 86.4 ks. The formation range of each phase was examined as a function of the hydrogenation temperature and the hydrogen pressure in the RNi2 (R=Sm, Ho, Er) compounds. The amorphous single phase was formed below about 500 K independent of the hydrogen pressure in SmNi2. On the other hand, it was formed in the range of 300-523 K and 2.0-5.0 MPa H2 in HoNi2, and in the range of 400-500 K and 4.0-5.0 MPa H2 in ErNi2.
The crystallization behavior of the amorphous a-RNi2Hx alloys prepared by hydrogenation was investigated by differential scanning calorimetry (DSC) . The amorphous alloys decomposed into c-RNi5+c-RH2 in the case of R=Sm and Gd, while they decomposed into c-RNi3+c-RH2 in the case of R=Dy, Ho and Er. Apparent activation energies for crystallization in these amorphous alloys were almost constant as about 150 kJ/mol in spite of the different crystallization behavior. Enthalpy changes in crystallization were about 3.7 kJ/mol except for ErNi2Hx. The crystallization temperatures of these amorphous alloys ranged from 628 to 672 K.抄録全体を表示PDF形式でダウンロード (1184K) -
石山 成志, 花田 修治, 和泉 修1990 年 54 巻 9 号 p. 976-984
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーOrientation dependence of twinning in commercially pure titanium was determined in both single crystals deformed in tension or compression and polycrystals deformed in tension. {\bar1012} and {11\bar22} twins in single crystals, and {\bar1012}, {11\bar21} and {11\bar22} twins in polycrystals occurred depending on the sense and direction of applied stress. It was observed that twinning generally occurred on a highly stressed system with a large Schmid factor for twinning. However, {\bar1012} twins which have smaller Schmid factors than those for {11\bar21} twins operated predominantly in the region where the angle between the tensile axis and basal pole is about 30∼40°. This suggests that {\bar1012} twins are formed more easily than {11\bar21} twins. The planar anisotropy of work hardening, which has been reported in tensile deformation of commercially pure titanium sheet, is satisfactorily explained by the orientation dependence of twinning presented in this study.抄録全体を表示PDF形式でダウンロード (2350K) -
田上 耕司, 中村 勝光, 松田 日出彦1990 年 54 巻 9 号 p. 985-990
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーSimple tension and stress relaxation tests are made in copper single crystals to investigate whether or not the mechanical equation of state holds and how the activation volume of dislocation motion changes at each stage of the stress-strain curve with three stages. The effect of inhomogeneous dislocation movement on the rate-controlling process is then discussed. Stress relaxation curves, plotted as log \dotγ vs logτ, can be superposed on each other and form a master curve only when they are translated within an individual stage. The slopes of the translation traces and the shapes of the master curves for the respective stages are different from each other. The lack of a single master curve indicates that the mechanical equation of state does not hold for a single crystal specimen. It is ascertained that the different shapes of the master curves are due to an unsuccessful application of the Arrhenius type rate equation for the deformation accompanied with the inhomogeneous movement of dislocations. The inhomogeneous plastic deformation may have no effect on the thermal activation parameters obtained under conditions of quasi-stationary dynamic equilibrium because the Arrhenius type rate equation is valid. On the contrary, it has a significant effect on them under conditions of non-stationary dynamic equilibrium because the rate equation becomes time dependent.抄録全体を表示PDF形式でダウンロード (929K) -
田上 耕司, 米田 博之, 藤井 浩二, 松田 日出彦1990 年 54 巻 9 号 p. 991-998
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーIt is investigated how the characteristics of secondary recrystallized grains grown both with and without a dopant and at the different rates of heating have an effect on the high temperature strengths concerned chiefly with creep of powder metallurgy tungsten wires. While the fracture mode is ductile or transgranular for doped wire with large elongated secondary recrystallized grains by slow heating, it is typically intergranular for non-doped wire. The stress exponent in the power law creep region shows the significant stress dependence due to the internal stress. Therefore, there may exist two factors affecting the stress exponent through the internal stress: (1) the bubbles existing in doped wire and (2) the characteristic configuration of secondary recrystallized grains. The deformation mechanism maps show that the large elongated grains can effectively suppress the creep strain at high temperatures.抄録全体を表示PDF形式でダウンロード (1264K) -
奥村 展, 井上 明久, 増本 健1990 年 54 巻 9 号 p. 999-1004
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーIt was found that amorphous La55Al25Ni20 and La55Al25Cu20 alloys exhibit a distinct glass transition and the temperature span between Tg and Tx, ΔTx(=Tx−Tg) exceeds 50 K, as evidence of the formation of an amorphous phase with ΔTx above 50 K in a metal-metal type system. With the aim of obtaining further information on the glass transition behavior and the properties of supercooled liquid, the changes in fundamental properties of specific heat (Cp), viscosity (η), yield tensile strength (σy), tensile elongation including elastic elongation (εf) and viscoelasticity by glass-supercooled liquid transition were examined for both amorphous alloys. The transition brought about significant changes in the above-described properties, i.e., for the La55Al25Ni20 alloy, an increase of Cp by 12 J/mol·K and εf from 2.43 to 188% and a dramatic decrease of η to below 1012 Pa·s and σy from 710 to 3.47 MPa. In addition, the complex modulus decreased from 33.5 to 1.79 GPa and the loss tangent increased rapidly from 9×10−3 to 3.32. Similar significant changes in the fundamental properties were also observed for another La55Al25Cu20 amorphous alloy and hence these amorphous alloys were concluded to be a typical glassy material.抄録全体を表示PDF形式でダウンロード (758K) -
江島 辰彦, 佐藤 讓, 山村 力, 林 昭夫, 山崎 智幸1990 年 54 巻 9 号 p. 1005-1012
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーViscosities of Pb-Sn binary melts were measured by the use of an oscillating viscometer with a graphite cylindrical crucible in order to study the effect of the compositional inhomogeneity of the melt on the viscosity measurements. It has not been clear how the compositional inhomogeneity affect the viscosity measurement. The reasons why the Pb-Sn binary alloy has been chosen were as follows. The Pb-Sn binary system shows an eutectic type of phase diagram, and there is a big difference between the densities of the components, Pb and Sn. Therefore, the Pb-Sn binary alloy would easily bring about compositional inhomogeneity between the upper and lower parts of the melts in the crucible. In this work, the viscometer has been modified to let the helium gas bubble into the melts so as to stir the melt completely. It was found that there was a difference between the viscosities observed for the melt stirred completely and the melt after solidification and remelting in the viscometer. Viscosity of the melt stirred shows a monotonous dependence against the composition, and the viscosity of the melt after remelting shows an irregular dependence with poor reproducibility. It is clear that the viscosity of the melt changes smoothly against the composition, although some investigators have pointed out singular composition dependence of the viscosity near the eutectic composition. on the basis of these results, it is concluded that the complete mixing of the melt is necessary for the measurements by the oscillating viscometer.抄録全体を表示PDF形式でダウンロード (1042K) -
吉武 道子, 吉原 一紘1990 年 54 巻 9 号 p. 1013-1017
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe diffusion behavior of substrate element into a deposited film was investigated. The observed systems were a Nb film/Ti substrate and a Ti film/Nb substrate. When the Nb film/ Ti substrate was heated in a vacuum, Ti diffused very rapidly in the Nb film. The pre-exponential factor of the diffusion constant of Ti in the Nb film was 5.6×10−2 m2s−1, and the activation energy was 220 kJmol−1. The observed activation energy is about 60% of that of Ti in the bulk Nb. On the other hand, when the Ti film/Nb substrate was heated in a vacuum, Nb did not diffuse so rapidly.
Titanium diffused through the Nb film rapidly and was concentrated on the surface of the Nb film. The chemical state of the concentrated Ti was metallic, and neither titanium oxides nor titanium carbide was observed. Therefore, the driving force of the rapid diffusion of Ti in the Nb film is considered as the reduction of the surface energy of Nb film. The difference in the diffusion behavior between Ti through the Nb film and Nb through the Ti film is explained supposing that the segregation of Ti reduces the surface energy of the Nb film but the segregation of Nb does not reduce the surface energy of the Ti film.
After heating of the Nb film/Ti substrate for a long time, a new phase was formed at the interface between the Nb film and the Ti substrate. The chemical composition of the new phase is about 50% of Ti and 50% of Nb. This phase has not been reported in the phase diagram of the bulk Ti-Nb system. The surface area of the Nb film is considered to be quite large, so the contribution of surface energy to the thermodynamic state of the Nb film cannot be neglected. Therefore, the chemical potential of the film is different from that of the bulk. Then, the new phase, which does not exist in the phase diagram of the bulk system, is formed by an interaction of the films.抄録全体を表示PDF形式でダウンロード (682K) -
戸嶋 茂郎, 水流 徹, 春山 志郎, 中川 善隆, 広瀬 祐輔1990 年 54 巻 9 号 p. 1018-1023
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe electrochemical behaviour of iron in methanol solutions has been investigated. In anhydrous methanol (<0.07%H2O), iron dose not exhibit definite passive behaviour. In the presence of water up to 5.0% content there is a decrease in anodic dissolution current and the passive behaviour is clearly observed. On the other hand, an active dissolution of iron occurs in the solution containing water more than 10% and consequently the corrosion rate increases. It is found that the corrosion rate of iron is governed by anodic reaction in the methanol solution with water contents up to 10%, whereas by the cathodic reaction in the methanol solution containing water more than 20%. The cathodic current in methanol solutions increases with increasing concentration of dissolved oxygen. However, the dissolved oxygen inhibits the anodic dissolution of iron. Hence the increase of the dissolved oxygen results in a decrease of the corrosion rate of iron.抄録全体を表示PDF形式でダウンロード (768K) -
中谷 功, 増本 剛, 高橋 聰, 西田 勲夫, 清沢 昭雄, 小口 信行1990 年 54 巻 9 号 p. 1024-1029
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThis paper shows the potential applications of the floating zone method to the growth of single crystals of InSb whose melts have high specific gravity and low surface tension.
The maximum diameter of the single crystals that can be obtained by the method about 5 mm, because the molten zones with sizes up to 5 mm in diameter can only be sustained against the gravitational froce. The most suitable conditions for growth of the InSb single crystals were described. This paper also presents a new method to measure the surface tension from the equilibrium shape of the molten zones. By the method the surface tension of the molten InSb is determined to be 0.290 N/m.
The single crystals obtained are characterized by X-ray topography, whose imperfections are mainly twining, stacking faults and dislocation loops.抄録全体を表示PDF形式でダウンロード (1146K) -
浦尾 亮一, 青山 正義, 神長 美代志, 大貫 光明, 三宅 保彦1990 年 54 巻 9 号 p. 1030-1035
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーThe effect of pre-heating at 873 K on the enhancement of softening rate of cold-drawn pure copper wires were studied in relation to the hot-working process and impurities of hot worked copper rods. Tough pitch coppers (TPC), southwire continuous rod (SCR) and oxygen free copper (OFC) rods were pre-heated at 873 K for 3.6 ks, and they were cold-drawn to 90% and finally annealed at 433-473 K within 60 ks. The annealed copper wires were subjected to the measurements of the hardness and crystal grain size, and structural observations.
When the copper rods pre-heated at 873 K are annealed after cold-drawing, the softening of the tough pitch copper with much lead is more accelerated than differently processed copper wires. The softening rate of SCR copper wire is more higher than that of tough pitch copper where the impurity concentration is similar to SCR.
It is known from the softening and grain growth behavior that the enhancement of softening is not due to the increase in growth rate of recrystallized grain but to the increase in nucleus generation.抄録全体を表示PDF形式でダウンロード (954K) -
旗手 稔, 炭本 治喜, 中村 幸吉1990 年 54 巻 9 号 p. 1036-1040
発行日: 1990年
公開日: 2008/04/04
ジャーナル フリーTaking note of the segregation of Ni in the primary austenite, the influence of C and Ni content was investigated on the linear thermal expansion coefficient (α) of Fe-Ni-C alloys. when C below 2 mass% was added to Fe- (34-40 mass%) Ni alloys above the Invar composition, the α value increased in the temperature range from 373 to 500 K. With more than 2 mass%C additions, the α value increased in the temperature range from 373 to 773 K. On the other hand, with the addition of C up to 3.42 mass%C to Fe-(27-30 mass%) Ni alloys below the Inver composition, the α value decreased in the temperature range from 450 to 750 K because the composition of the primary austenite is reaching the Inver composition. The α depends mainly on the Ni concentration and not on the graphite structure.
An effective distribution coefficient of Ni (keNi) in Fe-Ni alloys was smaller than unity, on the contrary, keNi in Fe-Ni-C alloys increased with increasing C content and was larger than unity. It was concluded that such a change in α was caused by the segregation of Ni in the primary austenite.抄録全体を表示PDF形式でダウンロード (888K)
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