巻号一覧
48 巻, 7 号
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研究論文
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佐藤 隆之介, 杜澤 達美, 加藤 一, 高山 善匡, 横林 知章1998 年 48 巻 7 号 p. 307-311
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe surface fatigue crack propagation behavior has been investigated under tension-tension cyclic stress at two different frequencies in 3 mass% NaCl aqueous solution for the 5052 and 5083 aluminum alloys, and 1100 commercially pure aluminum sheets with an artificial surface defect. While the fatigue life (number of cycles to failure) at low frequency is obviously longer than that at high frequency in 5083 alloy and 1100 aluminum, the fatigue life is almost independent of the frequency in 5052 alloy. The reduction of fatigue life is largest for 1100 aluminum containing almost no addition of Mg which generally improves corrosion resistance of an aluminum alloy. The fatigue life for 5083 alloy, which is assumed to have β phase more than 5052 alloy because of differences in Mg content and heat treatment, is lager than that for 5052 alloy. In the early stage of fatigue crack when propagation is governed by corrosion environment, surface crack propagation rate at low frequency tends to be slightly higher compared with that at high frequency for 5052 alloy. Further, the 5052 alloy exhibits the flatter front shape of fatigue crack at failure at the lower, because the surface crack propagation is more accelerated by corrosion effect.抄録全体を表示PDF形式でダウンロード (1317K) -
稲垣 敦也, 小松原 俊雄, 稲垣 裕輔1998 年 48 巻 7 号 p. 312-316
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe effects of test temperature and strain rate, on the yield point elongation of Al–Mg alloys were systematically investigated. Also the influences of Mg contents and grain sizes of the specimence were studied in detail. It was found that yield point elongation was almost constant below 337 K. Above 337 K, it decreased with increasing test temperature, disappearing completely at temperatures above 423 K. Yield point elongation was observed to increase linearly with increasing strain rate. With increasing grain size, yield point elongation showed a significant decrease, and above a critical grain size of 150 μm, its formation was completely suppressed. Yield point elongation increased remarkably with increasing Mg content. At higher Mg contents, however, yield point elongation decreased appreciably.抄録全体を表示PDF形式でダウンロード (833K) -
戸澤 康壽, 小野 宗憲1998 年 48 巻 7 号 p. 317-322
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe springback of bending at the die shoulder and the warp of web are discussed experimentally for the products formed by shrink, stretch and straight flanging of aluminum alloy sheets. The springback decreases with the decrease in die profile radius and this tendency is remarkable for larger flange height. When the die shoulder radius becomes large, the springback also becomes large. The springback angle correlates with the proof stress of sheet. The web of products warps downward for shrink flanging and upward for stretch flanging, though the web doesn't warp in case of straight flanging. The height of warp changes not monotonically but having a extreme value when the die profile radius decreases and finally the direction of warp turns to the opposite side. This phenomenon is explained by an analysis in which the warp is generated by both elastic recovery of flange and springback of die shoulder bending. The warp is decreased by reduction of flange height and it increases with increasing die shoulder radius in case of shrink flanging, while decreases in case of stretch flanging.The height of warp also correlates with the proof stress of sheet.抄録全体を表示PDF形式でダウンロード (900K) -
長谷川 浩平, 藤田 毅, 三田尾 真司, 大沢 紘一, 荒木 健治, 大堀 紘一, 新倉 正和1998 年 48 巻 7 号 p. 323-328
発行日: 1998年
公開日: 2007/06/01
ジャーナル フリーEffects of Mg content and intermediate annealing on r-value were studied in Al–Mg alloy sheets with Mg content of 0~7%. In the condition without intermediate annealing, r0 and r90 were higher than r45 in pure aluminum and Al–Mg alloys with Mg content less than 4%, while r45 was higher than r0 and r90 in Al–Mg alloys with Mg content more than 4%. The recrystallization texture was mainly {100}<001> in the former and {310}<132> in the latter. Intermediate annealing with the final cold rolling of about 30% increased r-value and decreased planar anisotropy in Al–Mg alloy sheets. The mean r-value, r, was higher with intermediate annealing than without intermediate annealing, and Mg content dependence of r was minimized with intermediate annealing in Al–Mg alloys with Mg content above 3%. The recrystallization texture was found to be very random and considered to be responsible for such effect of intermediate annealing. Light cold rolling of about 10% after intermediate annealing gave rise to high r with large planar anisotropy. The recrystallization texture was revealed to be {145} <321>, and was regarded to be caused by strain-induced grain boundary migration.抄録全体を表示PDF形式でダウンロード (1218K) -
鄭 秉準, 里 達雄, 手塚 裕康, 神尾 彰彦, 才川 清二, 中井 清之1998 年 48 巻 7 号 p. 329-334
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーMicrostructure and mechanical properties of an as-cast and heat-treated Al–7%Si–0.5%Mg– alloy (an alloy A357) produced by both the conventional mold casting and semi-solid process have been investigated. The effect of microstructural changes during heating to semi-solid temperatures on the mechanical properties are also discussed for the alloy produced by the semi-solid process. The microstructure of the produced alloy basically consists of the spherical α phase and fine eutectic silicon phase without any segregates and defects. The average size and volume fraction of the α phase are about 52 μm and 65 ±3%, respectively. The eutectic silicon phase becomes spheroidized by solution heat treatment. The ultimate tensile strength and elongation of the peak-aged alloy are 350 MPa and 16%, respectively. As the heating and holding times increase, the mean particle size of the α phase slightly increases. The increment, however, is negligibly small in the examined condition. Therefore, the mechanical properties of the alloy produced by the semi-solid process remain almost unchanged with increasing heating and holding times, compared with those of the non-heated alloy. Coalescence between α phase particles occurs with increasing heating and holding times, resulting in the shape change of the particles.抄録全体を表示PDF形式でダウンロード (1712K) -
小松 伸也, 池田 勝彦, 河本 知広, 田畑 義昭, 谷本 孝弘1998 年 48 巻 7 号 p. 335-339
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーAl–0 to 8.1 mass (0 to 8.9 at) %Mg solid solution alloys were annealed at 623 K for 3.6 ks (FA) after 92% final cold rolling and holding at room temperature for 60 Ms (CR–60 Ms). Resistivity was measured at 77 and 300 K(ρ77 and ρ300) before and after the annealing. Tensile test was carried out at room temperature with strain rate of 6.7 × 10−4s−1. Work hardening by the cold rolling was estimated from the difference in proof stress δσ0.2 = σ0.2CR-60Ms–σ0.2FA between the CR-60 Ms state and the FA state. For the solid solution alloys with Mg contents up to 5%Mg, the δσ0.2 due to the increase in dislocation density, NDISL, is related to the resistivity increment by the CR, δρ77=ρ77CR-6OMs− ρ77FA, as δρ0.2/MPa= 263 (δρ77/nΩm) 1/2 = 0.57 Gb (NDISL/m−2)1/2, where G is the rigidity modulus, 26 GPa, b is the magnitude of the Burgers vector, 0.29 nm, and the contribution to resistivity by the unit density of dislocation is 2.7 × 10−25Ωm3. For the alloys with Mg contents higher than 6%, the δσ0.2 is lower than expected from the above relation, perhaps because the ρ77CR, and therefore the δρ77, was increased by the contribution of G.P. zones formed during a prolonged holding at room temperature after the CR.抄録全体を表示PDF形式でダウンロード (1024K) -
中山 栄浩, 二ノ宮 克成, 大西 脩嗣1998 年 48 巻 7 号 p. 340-345
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe mechanical properties and aging processes were investigated for the Al–2%Si casting alloy containing various amounts of magnesium from 0.3 to 1.0%. The specimens were solution treated at high temperature and aged isothermally at the temperatures ranging from 418 to 473 K. Electrical resistivity measurement and differential scanning calorimetry showed that the formation of cluster increased with increase in magnesium content in the early stage of aging and the following aging processes were retarded by the formation of cluster. The peak value of proof stress and the aging time giving a peak value increased with increase in magnesium content. The elongation to fracture and absorbed energy of the specimens containing 0.6% Mg or more decreased remarkably, resulting from a crystallized Mg2Si particle existing in the eutectic portion. Both fracture elongation and absorbed energy were larger for Al–2%Si–0.3%Mg alloy than for AC4CH alloy.抄録全体を表示PDF形式でダウンロード (1316K) -
中山 栄浩, 二ノ宮 克成, 大西 脩嗣1998 年 48 巻 7 号 p. 346-351
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe mechanical properties of Al–2%Si–0.6%Mg casting alloy solution treated at temperatures ranging from 819 to 835 K have been investigated from the viewpoints of amounts of solid solutions and morphology of eutectic Si and crystallized Mg2Si particles. Mg2Si particle crystallized in a casting process was not soluble to the matrix even by heating at solidus temperature. The shape of eutectic Si and Mg2Si particles was remarkably improved by the solution treatment at 829 K for 10.8 ks and the fracture elongation and absorbed energy of this specimen increased markedly. Solution treatment at 829 K for 10.8 ks and subsequent aging at 418 K provided the alloy an excellent combination of strength and ductility in comparison to that of AC4CH and Al–2%Si–0.3%Mg alloys.抄録全体を表示PDF形式でダウンロード (1491K)
研究ノート
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高谷 松文, 橋本 和明, 戸田 善朝1998 年 48 巻 7 号 p. 352-353
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーPDF形式でダウンロード (418K)
解説
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浜田 登喜夫1998 年 48 巻 7 号 p. 354-360
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーPDF形式でダウンロード (2393K)
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