巻号一覧
56 巻, 11 号
選択された号の論文の18件中1～18を表示しています
- |<
- <
- 1
- >
- >|
-
山崎 徹, 嶋田 辰夫, 荻野 喜清1992 年 56 巻 11 号 p. 1229-1234
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe viscosity of liquid Fe-B-Si alloys has been measured by an oscillating crucible method in the temperature range from melting temperature (Tm) to about 1600 K. The viscosity of these alloys depends strongly on the composition. When the composition is located near a eutectic depression, the viscosity and the activation energies for viscous flow are drastically decreased, e. g., the activation energies obtained are 18.5, 32.2 and 50.9 kJ/mol for Fe79.5B12Si8.5 (near eutectic region), Fe81B11Si8 (hypoeutectic region) and Fe75B15Si10 (hypereutectic region), respectively. This may be due to the existence of some short range orders in the liquid, i. e., when the composition departs from the eutectic, Fe-rich order in the hypoeutectic region and Fe2B type order in the hypereutectic region are developed. These orders are suspended in the liquid and increase the viscosity and the activation energies. The viscosity below Tm is estimated from the Fulcher relation, i. e., ln η=−3.6582+734.1/(T−674) for Fe79.5B12Si8.5 and ln η=−4.1928+1934.1/(T−706) for Fe75B15Si10 where η: poise and T : K.抄録全体を表示PDF形式でダウンロード (809K) -
足立 吉隆, 中森 俊夫, 亀井 一人1992 年 56 巻 11 号 p. 1235-1241
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーWith special attention to hetero-epitaxial growth of FeZn13(ζ) crystals precipitated on 99.999% pure iron substrate, we have investigated the reaction between Fe and Zn during hot dip galvanizing. The results obtained are as follows.
(1) Hetero-epitaxial growth of ζ crystals on iron substrate is found.
(2) The epitaxial growth largely depends on the crystal plane of iron substrate. On (111)-(113)-(313)α the epitaxial growth occurs, while on (001)-(101)αζ crystals are oriented randomly.
(3) FeZn7(δ1) crystals are often precipitated at the interface between randomly oriented ζ crystals and iron substrate.
(4) ζ has [001]ζ axis as the growing axis and a diamond cross-section surrounded by four {110}ζ planes.
(5) The crystallographic relationship between ζ crystal and iron substrate is as follows;
(1\bar21)[\bar113]α\varparallel(110)⌈001⌋ζ
or
(2\bar11)[\bar113]α\varparallel(010)[001]ζ抄録全体を表示PDF形式でダウンロード (3370K) -
竹内 章, 小山 敏幸, 守屋 健, 宮崎 亨1992 年 56 巻 11 号 p. 1242-1247
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーComputer simulation of phase decomposition was performed for the G. P. zones of Al-Zn alloy system on the basis of the Cahn-Hilliard’s non-linear diffusion equation. In the calculation, the modified regular solution approximation was adopted, i.e. the composition and temperature dependences of the interaction parameter Ω between the nearest neighbor atoms were taken into account and the mobility of the system was defined as a function of solute composition.
Al-Zn alloy systems have asymmetry concerns with the solute composition on phase diagram, that is different from the alloy systems calculated in the previous papers where regular solution model and Cu-Co alloys.
The phase decomposition was successfully computed for the G. P. zones of Al-Zn alloy. The calculation method is applicable for the alloys, whose decomposition regions have asymmetry with solute composition.
It is expected that the simulation is useful in the analysis of phase decomposition process.抄録全体を表示PDF形式でダウンロード (790K) -
申 熙澤, 金子 純一, 菅又 信1992 年 56 巻 11 号 p. 1248-1256
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーPrecipitation hardening of a supersaturated solid solution of extended solubility obtained by rapid solidification has been studied on an Al-8%Mn-2%Cr alloy with or without addition of Zr or Ni. Rapidly solidified flakes were produced by using an apparatus combining gas-atomization and water-cooled copper single roll. P/M materials were consolidated from the flakes by cold pressing, vacuum degassing and hot extrusion. Precipitation hardening behavior was examined for both rapidly solidified flakes and P/M materials.
In age-hardening at 673 K, a higher peak hardness was attained and softening due to overaging was observed for a Zr-added alloy. TEM obsevation and X-ray diffraction revealed that the hardening due to ZrAl3 precipitation was superimposed on that due to ternary G-phase ［(Mn, Cr)Al12］. Nickel addition caused a significant delay of precipitation hardening due to the formation of a ternary compound Al16Mn3Ni. Both Ni and Zr additions increased the tensile strength as well as the elongation of as-extruded materials. However, the fully precipitation hardened materials showed extremely poor tensile ductility at room temperature.抄録全体を表示PDF形式でダウンロード (2732K) -
岡本 尚機, 岡 宗雄1992 年 56 巻 11 号 p. 1257-1265
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーA practical procedure for determining uniquely the habit planes of martensite plates with {112}α transformation twins observed by means of transmission electron microscope is presented. The procedure includes one-surface trace analyses of habit and transformation twin planes, and the analysis of the orientation relationship between austenite and martensite. Three applied examples with different foil orientations are shown for thin-plate martensites with {3 15 10}γ habit plane containing {112}α twin in an Fe-24.67 mass%Ni-0.87 mass%C alloy. The possibility of a unique determination using the trace data depends entirely upon the foil orientation. Therefore, the foil orientations are classified into three groups; (i) {100}γ and {110}γ mirror symmetry planes;—impossible, (ii) orientations around the mirror symmetry planes;—possible in combination with the analysis of the orientation relationship, and (iii) other orientations than (i) and (ii);—possible. A least square method to determine the mean habit planes by a number of one-surface trace analyses is proposed. The mean habit plane obtained is the (0.1969 0.7829 0.5901)γ, and its standard deviation is evaluated to be ±4.4° in the present thin-plate martensite.抄録全体を表示PDF形式でダウンロード (1741K) -
小山 敏幸, 宮崎 亨1992 年 56 巻 11 号 p. 1266-1271
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe time evolution of the phase transformation has usually been analyzed by the differential equation containing the time dependent term, such as the diffusion equation. On the other hand, the energetic analysis has been utilized in the description of the morphologically slow process such as the coarsening of precipitates in the later stage of phase decomposition. Thus, both the analyses have conventionally been used properly in describing the phase decomposition. However, the propriety of the energetic analysis of the phase decomposition, particularly on the early stage of phase decomposition, has quantitatively not been investigated.
In this study, the progress of two typical phase decompositions, i. e. the nucleation-growth and the early stage of spinodal decomposition, is theoretically studied on the basis of the kinetic and the energetic analyses, respectively. The results obtained are as follows:
The kinetic path exhibited in the calculation on the basis of the diffusion equation is elucidated to be consistent with the energetic minimum path evaluated by the theory of the system free energy. This result indicates that the energetic analysis is effective, even for the comparativebly early stage of the phase decomposition.抄録全体を表示PDF形式でダウンロード (935K) -
向後 保雄, 香川 豊, 八田 博志1992 年 56 巻 11 号 p. 1272-1279
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe fracture toughness test was carried out on partially-stabilized zirconia under mode I and mixed mode conditions of mode I and mode II. Before the fracture toughness test, the initial crack shape introduced by knoop indentation was evaluated. The initial cracks was classified into two groups: they are initial cracks consisting of the knoop indentation only and those consisting of the knoop indentation with an ellipsoidal crack growing from the knoop indentation. The four-point bending test on the knoop-indented specimens and the fracture surface observation revealed that the specimens with the ellipsoidal crack were suitable for fracture toughness test.
The indented and fracture surface observations clearly showed the existence of an ellipsoidal region, in which the diameter was larger than that of the initial ellipsoidal crack generated by knoop indentation. The larger region was deduced to correspond to stable crack growth during the mode I fracture toughness test. The effect of residual stress on the measured fracture toughness by knoop indentation was examined. The mixed-mode fracture toughness test was also carried out, and the stable crack growth was also observed even under a mixed mode condition. These results of the fracture toughness test indicated the existence of the R-curve behavior of zirconia both in the mode I loading condition and in the mixed mode loading conditions of modes I and II.抄録全体を表示PDF形式でダウンロード (2357K) -
向後 保雄, 香川 豊, 八田 博志1992 年 56 巻 11 号 p. 1280-1288
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーFracture toughness of SiC whisker and ZrO2 particle reinforced alumina matrix composite was investigated under modeI and modeII loading conditions.
Under modeI loading condition, the critical stress intensity factor increased with increasing ZrO2 volume, which well agreed with theoretical estimation. It was also shown by the theoretical analysis that the transformation of ZrO2 was less effective to the toughness of the composite under modeII loading, which was consistent with the experimental results.抄録全体を表示PDF形式でダウンロード (3274K) -
中山 栄浩, 鷹合 徹也1992 年 56 巻 11 号 p. 1289-1295
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe effect of textures on the relations between the lattice strain and sin2ψ, observed in the cold rolled 5083 aluminum alloy, has been studied by referring to the values calculated basing upon the Reuss’s model. Generation mechanisms of the residual stresses during the cold rolling of the 5083 aluminum alloy were also discussed in connection with the existence of macroscopic and microscopic residual stresses. The results obtained in the present study are summarized as follows:
(1) Nonlinear relations existed between the lattice strain and sin2ψ in the cold rolled 5083 aluminum alloy specimen. Linear relations, however, existed between the lattice strain generated per applied unit stress and sin2ψ. The measured values of the lattice strain corresponded with the values calculated on the basis of the Reuss’s model.
(2) Macroscopic residual stresses, measured in the 30% cold-rolled specimen, were effected by microscopic residual stresses.抄録全体を表示PDF形式でダウンロード (1016K) -
富田 友樹, 高谷 泰之, 原田 良夫, 永井 健介1992 年 56 巻 11 号 p. 1296-1302
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーIn previous studies, Ni-Cr overlay alloy containing NbC particles, formed by a plasma powder welding process, was found to exhibit excellent wear and corrosion resistances. It is necessary for further improvement of the wear property to make dispersed NbC particles as small as possible. However, any overlay alloy with dispersed NbC particles having a diameter below a few micron, has not been yet obtained, because of restricted size of powder to be used in this process.
In this paper, in order to develop such a overlay alloy with finely dispersed NbC particles, a composite powder, which was made from NbC powder (1.3 μm), Ni-20 mass%Cr alloy powder (<10 μm) and pure Cr powder (<10 μm) by mixing, granulating and sintering, was appllied to this process at various plasma arc currents in the range of 80 to 200 A. The effect of plasma arc current on dissolution and dispersion of NbC particles has been studied by SEM, TEM, EPMA and XRD. The following results were obtained.
At the range of 160 to 200 A, NbC particles completely melted and coarse primary NbC appeared during solidification. At 120 A, the added NbC particles having a diameter of a few micron remained almost unmelted and were dispersed uniformly in the overlay alloy. However, at 80 A, although the added NbC particles did not melt, a large amount of weld defect occurred in the overlay alloy because of a lack of heat input.抄録全体を表示PDF形式でダウンロード (2450K) -
Hiroyuki Toda, Toshiro Kobayashi, Mitsuo Niinomi1992 年 56 巻 11 号 p. 1303-1311
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe majority of existing models which predict mechanical properties of composites assume that matrix properties are unchanged by presence of reinforcement. However, preliminary investigations have shown that there are never negligible effects of the reinforcement on the matrix microstructure. For example, accelerated aging of the composite has been reported recently. The objective of this article is to document the effects of the reinforcement on the aging response of the cast 6061 aluminum matrix.
Cast reinforced composites containing 22% volume fraction of silicon carbide whisker were fabricated by high pressure infiltration technique. The age-hardening behavior of the 6061 aluminum alloy with and without SiC whisker was studied using hardness measurement, calorimetric technique and transmission electron microscopy.
The over-all age-hardening sequence is not altered by the addition of SiC whisker. Moreover, the maximum hardness of 6061 with and without SiC whisker is associated with the same transition stage from the GP(II) zone to the intermediate β′ phase. However, precipitation kinetics of the matrix alloy is affected by presence of the reinforcement. Times to achieve the peak hardness are shortened in the composites over the whole temperature ranges investigated. But this tendency becomes remarkable with low aging temperature, suggesting the contribution from high diffusivity paths such as dislocations and reinforcement-matrix interfaces. This acceleration is attributed to the drastic decrease of the activation energy required for the formation of the GP(II) zone and intermediate β′ phase. In contrast, the GP(I) zone formation is slightly retarded by the whisker. Furthermore the fraction transformed data were fitted to the Johnson-Mehl-Avrami type time dependence expressions and reaction rate order, n, is obtained as a function of temperature. The data explain a role of dislocations as precipitation sites. Finally microscopic observation was performed to confirm the above-mentioned experimental results.抄録全体を表示PDF形式でダウンロード (1666K) -
戸田 裕之, 小林 俊郎1992 年 56 巻 11 号 p. 1312-1321
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe fatigue crack growth characteristics of SiC whisker reinforced cast 6061 aluminum alloy matrix composites were investigated. The samples of MMCs were tempered under three aging conditions. The role of crack closure was also appreciated from a compliance measurement. Furthermore in the higher ΔK region, the fatigue crack growth characteristics were evaluated employing the experimentally obtained and converted J-integral value.
Fatigue crack growth resistance including fatigue thresholds for MMCs exceeds that for the unreinforced alloy. However, fatigue crack growth rates of MMCs are remarkably accerelated in the stage IIb, and the da/dN-ΔK curves of MMCs and unreinforced alloy intersect during the stage IIb. Moreover, MMCs fracture unstably and rapidly at much lower growth rates than the unreinforced alloy in the stage IIc. In all the matrix aging conditions, the underaged MMC exhibits superior fatigue crack growth resistance. This is considered primarily due to crack-closure from the da/dN-ΔKeff plots which subtract out the influence of crack-closure, and also due to crack tip shielding such as damaged zone, crack deflection and uncracked ligament.
In the stage IIa of MMC, the plastic zone is so small that the stresses ahead of major crack are not su･cient to fracture SiC whiskers. Therefore the crack propagates smoothly in the matrix and when it comes at a whisker, the crack tends to avoid a whisker, thereby promoting whisker pull-out. With increasing ΔK level, the fracture process zone develops within the plastic zone, so the main crack propagates toward subcracks ahead of crack tip and crack deflection becomes remarkable. Therefore in the stages IIb and IIc the fracture surface becomes rough with increasing ΔK.抄録全体を表示PDF形式でダウンロード (3958K) -
井上 尚三, 内田 仁, 徳永 洋一, 小寺澤 啓司1992 年 56 巻 11 号 p. 1322-1328
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーTiN films have wide-ranging applications from erosion resistant coatings for cutting tools to diffusion barriers in LSI devices. The purpose of this work is to investigate the growth process of reactive sputtered TiN films.
TiNx films were deposited onto air cleaved (001)NaCl single crystals by rf sputtering of 99.9%Ti disk (70 mm in diameter) with Ar+N2 mixed gas. Total gas pressure during sputtering (Ptotal) was 0.4 Pa. The N2 partial pressure-to-total pressure ratio (PN2/Ptotal), substrate temperature (Tsub) and rf power (Prf) were changed 0.0∼0.5, R. T.∼300°C and 100∼300 W, respectively. The microstructure of the films was studied by transmission electron microscopy.
A deposition rate decreased with increasing PN2/Ptotal and decreased drastically when PN2/Ptotal increased above a threshold value. The threshold value was about 0.25 at Prf 300 W. It was shown that the films prepared at above the threshold value were gold colored and had TiN structure. Although a microstructure was constructed by fine grains, the gold colored film showed strong preferred orientation, which was (001) TiN\varparallel(001)NaCl. The higher substrate temperature and the higher applied rf power resulted in the larger grain sized film. It was considered that growth process of TiN films was based on a three dimensional nucleation. Unfortunately, reproducibility was not so good, it was suggested that (001)TiN single crystal films were able to grow on (001)NaCl at 300°C, which was lower than the reported epitaxial temperature of TiN films on MgO single crystal.抄録全体を表示PDF形式でダウンロード (2121K) -
大沼 寛, 宮田 保教1992 年 56 巻 11 号 p. 1329-1335
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe morphology of dendrite in the supercooled melt will be influenced by the natural convection in the melt. A numerical simulation program based on FEM is developed for 2-dimensional viscous fluid flow with natural convection. The program is applied to the melt flow around a dendrite. The effects of natural convection on dendrite, which grows upward or downward to the gravity in supercooled melt of the pure succinonitrile, are analyzed by this code. It is shown that the flow affects largely to the heat flux from solid to liquid (in supercooled melt) around the dendrite tip in the lower growth rate. The temperature gradient on the interface behaves characteristically corresponding to the direction of flow near the dendrite tip.抄録全体を表示PDF形式でダウンロード (921K) -
佐藤 忠夫, 宮川 俊二, 嶋影 和宜1992 年 56 巻 11 号 p. 1336-1342
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーTiAl/5∼50 mol%TiB2 composite materials and TiAl were prepared through solid state powder processing, consisting of the mechanical alloying where heptane, grinding aid, was added, and the hot isostatic pressing.
(1)Ball-milling of the powder mixture of Ti and B for more than 50 h can produce mechanically alloyed compound powder composed of TiB2 and TiB.
(2)The HIP sintered compact of the mechanically alloyed amorphous TiAl powder was composed of γ-TiAl with a small amount of Ti3Al and Al2Ti4C2. Al3Ti, TiB and TiC appear via solid state reaction in the sintered composites of the powder mixture of amorphous TiAl and mechanically alloyed TiB2. The amount of TiAl, Al3Ti and Al2Ti4C2 in the composites decreased with an increase in the powder mixing ratio of TiB2 to TiAl, while TiB2 and TiC increased. The TiB2 phase in the composite structure is particle-dispersed as islands of 10∼50 mm size.
(3)The micro-vickers hardness of the sintered composite materials increased with an increase in the mixing ratio of the TiB2 powder to the TiAl one, and reached a maximum value of 1200 Hv at the TiAl/25 mol%TiB2 composition.抄録全体を表示PDF形式でダウンロード (1752K) -
三浦 誠司, 小池 基行, 三島 良直, 鈴木 朝夫1992 年 56 巻 11 号 p. 1343-1351
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーThe plastic behavior of Ni3(Si, Ti) single crystals with 10 at%Ti is investigated, and the effects of temperature, strain-rate and crystallographic orientation with respect to stress axis are examined. An appreciable orientation dependence of critical resolved shear stress (CRSS) is found at 77 K, where the CRSS increases as the orientation shifts from ［001］ toward ［\bar111］. The apparent activation energy for the positive temperature dependence of strength, U, is evaluated to be 7.1 to 7.7 kJ/mol which is smaller than Ti free Ni3Si and is in good agreement with that expected from the data in polycrystals. For orientation near ［001］, where the octahedral viscous flow governs the steady-state deformation following characteristic yield drop, the stress exponent is found to be about 7 which is considerably higher than the values of 3.5-5 in other L12 compounds. The decrement in CRSS by the yield drop is unusually small as compared to the other L12 single crystals. The activation energy for the steady-state deformation is evaluated to be comparable to the value for diffusion of Si in Ni3Al. A good oxidation resistance of the alloy is also made clear in the present work.抄録全体を表示PDF形式でダウンロード (1266K) -
吉村 博文, 木村 欽一, 林 正之, 石井 満男, 花村 年裕, 高村 仁一1992 年 56 巻 11 号 p. 1352-1359
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーTitanium alloys can be hydrogenated with large amounts of hydrogen and dehydrogenated in vacuum at elevated temperatures. This paper aims at the equiaxed grain refinement and the improvement of mechanical properties of titanium alloys utilizing this phenomenon. Particular attention has been drawn to the control of three different types of dislocation structures introduced by the following treatments:
(1) Precipitation of hydrides: On aging of hydrogenated titanium alloys, high-density dislocations are introduced in the interior of hydrides and also in the surrounding region.
(2) Formation of cell walls by hot-working: The β transus temperature is decreased by hydrogenation so that the hot-working temperature can be lowered enough to retain the dislocation cell structure due to defomation.
(3) Martensitic transformation: On cooling from the β phase region of hydrogenated titanium alloys, high-density dislocations with the uniform distribution are introduced in acicular martensites.
The factor (1) gives rise to the localized structure of high-density dislocations which provides with heterogeneous nucleation sites for recrystallization, leading to the grain refinement. The factor (2) gives high-density dislocation cell structures to act as precipitation sites for hydrides, and the factor (3) causes the subdivision of the β-phase grain into fine martensite leaves with variants, in addition to uniformly distributed dislocations in the martensite matrix which serve for the precipitation of hydrides.
The combination of these factors such as (3)-(1) and (3)-(2)-(1) results in the grain refinement of the α+β type titanium alloys containing 0.2∼1.0 mass% hydrogen. For example, a Ti-6Al-4V alloy hot-rolled, quenched, aged, and recrystallized as well as dehydrogenated has ultra-fine grains of about 1 μm or less in diameter and has exhibited high strength, high fatique limit and excellent superplastic behavior.抄録全体を表示PDF形式でダウンロード (1731K) -
本田 紘一, 香川 豊1992 年 56 巻 11 号 p. 1360-1369
発行日: 1992年
公開日: 2008/04/04
ジャーナル フリーA new “Protrusion” technique, which utilize protrusion behavior after a longitudinal compression test, for the measurement of interfacial shear sliding stress has been developed. The analytical procedure for the calculation of the shear stress from room to elevated temperature was obtained and the model experimental results on single SiC fiber-reinforced borosilicate glass matrix model composite were compared with the theoretical calculation. The results of the model composite indicated that the applied stress versus protruded length showed reasonably good agreement between the measured protruded length and calculated data. The obtained interfacial shear sliding stress showed reasonable agreement with the value measured by another technique. The technique was also applied to the measurement of the interfacial shear stress in SiC fiber-reinforced LAS-II matrix composite to investigate possibility of the technique for engineering composite. The result showed that both the distribution of the shear stress and temperature dependence of them were obtained from one protrusion test. It was concluded that the advantages of the protrusion technique are: i) no need for special equipment, ii) mapping of interfacial shear stress can be obtained, and iii) possible to apply for elevated temperatures without any special equipment. Some discussion on the temperature dependence of measured interfacial shear stresses are presented.抄録全体を表示PDF形式でダウンロード (2008K)
- |<
- <
- 1
- >
- >|