巻号一覧
39 巻, 11 号
選択された号の論文の17件中1～17を表示しています
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古城 紀雄, 堀 茂徳1989 年 39 巻 11 号 p. 745-750
発行日: 1989/11/30
公開日: 2008/10/30
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東 健司1989 年 39 巻 11 号 p. 751-764
発行日: 1989/11/30
公開日: 2008/10/30
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大澤 泰明, 西村 尚1989 年 39 巻 11 号 p. 765-775
発行日: 1989/11/30
公開日: 2008/10/30
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小林 勝, 弘津 禎彦, 大谷 吉春, 高橋 健, 舘村 誠1989 年 39 巻 11 号 p. 776-782
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリー4mm thick sheets of 7475 aluminum alloy were processed by solution treatment at 480°C for 3h, warm-rolled at 200-260°C and annealed at 400°C for 1h, rolled at -150°C to 1mm thickness and annealed at 150°C for 5min, and finally rolled at -150°C to 0.95mm in single pass. The specimen rolled at the cryogenic temperature showed an extremely large elongation and a small flow stress at 517°C with an initial strain rate 5×10-4s-1. This superplastic behavior is caused by the presence of very small recrystallized grains produced in the sequence of processing of heavy and skin-pass rolling at cryogenic temperature with an intermediate annealing at low temperature. Generation of very fine grain structure was observed and analyzed with transmission electron microscopy. The fine grain structure was retained during superplastic deformation and supressed the cavitation.抄録全体を表示PDF形式でダウンロード (2152K) -
村松 尚国, 洪 侖義, 遠藤 孝雄1989 年 39 巻 11 号 p. 783-790
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーSuperplastic elongation, and the changes in microscopic feature and (111) pole figure with strain were investigated on an as-warm rolled 7475 aluminum alloy deformed under various increasing temperature conditions. The optimum condition for superplasticity was as follows: The deformation temperature is about 770K. The initial strain rate is 1×10-3 s-1 and the starting deformation temperature is 590K. The maximum elongation obtained under the above condition was 965%. This is much greater than the maximum one attained under the deformation at constant temperatures. Microscopic observation showed that the discontinuous recrystallization was suppressed by concurrent straining. The as-warm rolled specimens recrystallized continuously under increasing temperature conditions, and recrystallized discontinuously in case where the production of nucleus for discontinuous recrystallization was allowed before the onset of deformation. The larger superplastic elongation obtained in the deformation under increasing temperature condition was ascriable to the grain refinement due to continuous recrystallization.抄録全体を表示PDF形式でダウンロード (1461K) -
岩崎 源, 入江 佳洋, 速水 哲博, 東 健司, 伊藤 太一郎1989 年 39 巻 11 号 p. 791-797
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーThe effects of the conditions for high temperature annealing prior to deformation has been investigated for superplastic 7475 aluminum alloy on the microstructural features involved in the initiation stages of cavity formation. The superplastic elongation to failure, deformed at 793K with a strain rate of 2×10-4s-1, increases from 550% up to 800% with prior annealing time at high temperatures. This increment in elongation may be led by decrease in the volume of cavities forming with the superplastic strain. The microstructural observations made concerning the relation between superplastic cavitation and an initial formation of cavity suggest that numerous pre-existing spherical voids, probably formed during the thermomechanical processing, appear to be associated with hydrogen due to the peritectic reaction of an Al-Fe-Si phase→Al-Fe-Cu phase+liquid in Al-Zn-Mg-Cu type alloys. These voids seem to be obviously pre-existing nuclei of superplastic cavities. Hydrogen pore formation assisted superplastic cavity growth can be eliminated by high temperature diffusion prior to superplastic forming.抄録全体を表示PDF形式でダウンロード (1754K) -
岩崎 源, 入江 佳洋, 速水 哲博, 東 健司, 伊藤 太一郎1989 年 39 巻 11 号 p. 798-804
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーSuperplastic deformation behavior of fine grain 7475 aluminum alloy at 788K was characterized up to large plastic strain by means of both tensile tests of constant strain-rate and constant velosity. Significant hardening in constant strain-rate test and softening in constant velosity test were showed in the deformation. The occurrence of deformation in constant strain-rate test induced grain growth which explains nearly all of the hardening were observed in the microscopic studies. The stress-strain behavior deformed in constant velosity test is determined by the strain-rate history. The strain-rate sensitivity, m, is found to keep the initial value and decreases after larger strain as a result of concurrent grain growth. The stress-strain-rate behavior determined initially might not be applicable after large amounts of plastic strain. The strain-rate obtained maximum superplastic elongation is agreement with that where larger m has been kept up to larger strain. The reason why the larger elongation shows at higher strain-rates in constant velosity tests than constant strain-rate tests may be the maintain of large m value during superplastic deformation.抄録全体を表示PDF形式でダウンロード (907K) -
広橋 光治, 浅沼 博1989 年 39 巻 11 号 p. 805-810
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーNew strain rate sensitivity factors α and γ values have been defined respectively as power indices of changing rates of depth and diameter of hollows obtained by high temperature indentation test, and examined to evaluate superplasticity in the 7475 aluminum alloy sheet. The α and γ values for this alloy are proportional to each other and show the same tendency as the ordinary m value and total elongation. The values themselves are a little larger than that of m. Though the m-value and total elongation of the tested sheet are found to be small, the α and γ values are predictive of the deformation behaviour.抄録全体を表示PDF形式でダウンロード (1101K) -
小松原 俊雄, 松尾 守, 田形 勉1989 年 39 巻 11 号 p. 811-816
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーEffects of distribution of coarse precipitate (η-phase) and partial solutioning on grain size of superplastic 7475 aluminum alloy has been studied. It appears that the grain size before overageing is important because coarse η-phase tends to precipitate along and on triple points of grain boundaries. Final recrystallized grains can be refined by dispersing the coarse η-phase on the fine initial grain boundaries. Partial solutioning of small precipitates are found to be effective for additional grain refining because combination of large particles and matrix stregthening increases the nucleation sites. The experiments for superplastic properties were also conducted.抄録全体を表示PDF形式でダウンロード (1642K) -
吉田 英雄, 田中 宏樹, 土田 信1989 年 39 巻 11 号 p. 817-823
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーThe superplasticity of extruded rods and rolled sheets have been investigated in 2090 (Al-Cu-Li-Zr) and 8090 (Al-Li-Cu-Mg-Zr) alloys. The optimum temperature of extrusion to obtain superplasticity is 673K in 2090 and 573K in 8090. Stable substructures are formed during extrusion at such a comparatively low temperature. These substructures bring about the formation of fine recrystallized grains during deformation at higher temperature and result in excellent superplasticity. The above two optimum temperatures correspond to the precipitation of T1-in 2090 and T2-phase in 8090, respectively. It is considered that the precipitation of these phases contribute to the formation of the substructures. Rolling conditions were decided on the basis of extrusion. A 2090 sheet rolled at 673K shows the elongation of 980% in L-and 660% in T-direction at 773K with a strain rate of 5.6×10-3s-1, while an 8090 one rolled at 573K shows isotropic superplasticity, that is, the elongation of about 1000% in both directions at 573K in the wide range of a strain rate, 10-3-10-2s-1.抄録全体を表示PDF形式でダウンロード (2622K) -
都筑 隆之, 高橋 明男1989 年 39 巻 11 号 p. 824-830
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーThe influence of hydrostatic pressure on the cavitation, effect of atmosphere for forming and solution treatment on the final tensile strength, and the optimum aging condition for superplastically formed material were investigated experimentally in order to optimize the process variables for superplastic forming of 8090 aluminum alloy. Cavitation can be completely eliminated by the application of hydrostatic pressure greater than 40% of flow stress, when the true strain is less than 1.1. Degradation due to lithium loss during superplastic forming and solution treatment can be prevented by treatment in Ar gas atmosphere. Superplastically formed 8090 aluminum alloy aged at 160°C for 70-100h exihibits excellent tensile strength, greater than 480MPa. The door panel was fabricated successfully in accordance with the process and variables established by results described above.抄録全体を表示PDF形式でダウンロード (1461K) -
今井 恒道, 馬渕 守, 戸澤 康壽1989 年 39 巻 11 号 p. 831-835
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーβ type-Silicon Nitride (Si3N4) whiskers were mixed in organic solvent uniformly with 2124 aluminum alloy powder and fabricated into β-Si3N4 whisker reinforced aluminum composite (Vf=0.20) by hot pressing in vacuum, re-forging, and hot extrusion. Relationship between mechanical properties of the composite and strain rate at 525°C was investigated. Flow stress increases remarkably with increasing strain rate in the case of the strain rate more than 0.05s-1, where the m-value is 0.5. This is the case of superplastic deformation. Total elongation of the composite reaches 200-250% at the strain rate of 0.17s-1. Whiskers are still dispersed homogeneously in matrix after superplastic deformation. Although voids form at the interface between matrix and whisker or precipitates, the fracture surface of the composite at the strain rate of 0.17s-1 is covered by many dimples.抄録全体を表示PDF形式でダウンロード (1688K) -
西村 尚, 伊藤 達也, 山本 弘圀, 若山 修一1989 年 39 巻 11 号 p. 836-842
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーBending processing of fiber reinforced metal was attempted. Materials used were single layer continuous boron fiber reinforced superplastic alloys (SPZ: Zn-22%Al), which were fabricated under the optimum condition determined elsewhere. V bending tests were carried out at 250°C, and the effects of the fiber locations and matrix superplasticity on the shape of bent specimen and punch load were investigated. In the case of non-superplastic metal matrix, successful bending is difficult and accompanied with fiber fractures, especially for the FRM with inside or outside fiber locations. On the other hand, when matrix metal show superplasticity, specimens are bent successfully without fiber fractures regardless of fiber locations. Furthermore, matrix superplasticity decreases the punch load due to the low flow stress of matrix metal. It has been made clear by L bending tests carried out for the investigation of the minimum bending radius that matrix superplasticity enhances the minimum bending radius until that of the unrestrained single fiber. The evaluation of strength of bent composites has shown that the heat treatment to remove the superplasticity from matrix metal increases the strength of bent specimen.抄録全体を表示PDF形式でダウンロード (1679K) -
西村 尚, 伊藤 達也, 山本 弘圀, 若山 修一1989 年 39 巻 11 号 p. 843-847
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーMaterials were SPZ matrix and multiple layers of boron fibers, and they were fabricated by powder metallurgical technique. The composite with maximum fiber layers (=7) had the volume fraction of fiber of 23% and the strength of 700MPa at 250°C. The number and intervals of fiber layers were varied respectively, in order to investigate those effects on the bending properties. The increase of the number and intervals causes the increase of punch load. The effect on the minimum bending radius show complex features. For small fiber interval composites, fibers embedded into matrix metal fracture, while, for large number of fiber layers, the interval between fibers and surface is so small that fibers protrude from surface and fracture. Consequently, it has been made clear that the number and intervals of fiber layers should be optimized. The bending of composite with maximum volume fraction fibers of 20% (fiber layer intervals: 0.1mm, fiber layer number: 5) is successful.抄録全体を表示PDF形式でダウンロード (1100K) -
小島 陽1989 年 39 巻 11 号 p. 848-849
発行日: 1989/11/30
公開日: 2008/10/30
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渋江 和久1989 年 39 巻 11 号 p. 850-862
発行日: 1989/11/30
公開日: 2008/10/30
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佐藤 英一郎1989 年 39 巻 11 号 p. 863-864
発行日: 1989/11/30
公開日: 2008/10/30
ジャーナル フリーPDF形式でダウンロード (284K)
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