巻号一覧
51 巻, 4 号
選択された号の論文の9件中1～9を表示しています
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研究論文
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山田 健太郎, 里 達雄, 神尾 彰彦2001 年 51 巻 4 号 p. 215-221
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーThe cluster formation and two–step aging behavior of Al–1.4%Mg2Si and Al–1.4%Mg2Si–0.3%Si alloys were investigated using low-temperature adiabatic calorimetry, hardness measurement, electrical resistivity measurement and transmission electron microscopy. The specific heat changes in the alloys aged at low temperatures clearly demonstrated the existence of two exothermic peaks at temperatures between 273 and 343 K and higher than 343 K. These exothermic peaks were attributed to the formation of two types of pre-precipitates; i.e. Si-rich clusters and GP zones. The formation of these pre-precipitates was also detected by the electrical resistivity and hardness changes. The complicated two-step aging behavior of the present Al–Mg–Si alloys were well understood by taking into account the stability at higher temperatures and the effectiveness on the nucleation sites for the β″ phase of Si-rich clusters and GP zones during the final aging. The Si-rich clusters give a negative effect on the two-step aging phenomena is proposed. As the both pre-precipitates are formed competitively, such heat treatments as to give priority to the GP zone formation are effective to control the negative effect of the two-step aging and to increase age-hardening of Al–Mg–Si alloys.抄録全体を表示PDF形式でダウンロード (567K) -
大崎 修平, 伊藤 大介, 中井 学2001 年 51 巻 4 号 p. 222-227
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーStress corrosion cracking (SCC) behaviors of extruded 7050 series aluminum alloys in T6 and RRA (Retrogression and re-aging) tempers were studied as compared with that of the conventional 7075 aluminum alloy. 7050 and 7055 aluminum alloys in T6 showed a superior balance among strength, fracture toughness and SCC resistance above 7075–T6. The threshold stress intensity KISCC for SCC initiation can be ranked in the order of 7075 < 7050 < 7055, together with the SCC growth rate da/dt in the order of 7050 < 7055 < 7075. The alloys in RRA1 having a higher tensile strength than each of them in T6 exhibited an improved da/dt of 1/30∼1/50 below that of T6, and 7050–RRA2 showed a more reduced level below 1/100. Based on the test results and metallographic observation, KISCC of the alloys in T6 can be derived to agree with the KI condition when the crack tip plastic zone expands over the diameter in the R (radial) direction of fiber formed unrecrystallized grains, so that it is supported the SCC process in T6 materials is controlled by hydrogen embrittlement due to the dislocation transport of hydrogen and accumulation at grain boundaries. The contribution of anodic dissolution, on the other hand, is evident in RRA materials.抄録全体を表示PDF形式でダウンロード (813K) -
大崎 修平, 原 憲一郎2001 年 51 巻 4 号 p. 228-233
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーUniaxial tensile property and plane strain fracture toughness KIVj of Al–Li alloys 2090, 2091 and 8090 were examined as functions of aging condition and plate orientation. Each relation between KIVj and yield strength is presented separately with respect to the short-transverse (S) direction and the longitudinal (L) direction of a plate. The superior combination of strength and toughness in the L–T orientation compared with the S–L orientation is produced by transgranular fracture (TGF) and an effect of crack-divider delamination, where T designates the long-transverse direction. The fracture surface profiles in the S–L specimens were measured with a laser focus-displacement instrument to analyze the area fractions, fi and ft corresponding to IGF (intergranular fracture) and TGF, respectively. The fracture toughness evaluated by relating fi and ft with the fracture strain energy density in the tensile test is found to be in a good correlation with the measured KIVj. It is supported that the fracture in the Al–Li alloys occurs in terms of the characteristic distance ahead of crack, comparable with the mean spacing of coarse inclusion particles.抄録全体を表示PDF形式でダウンロード (474K) -
山室 正明, 森崎 重喜2001 年 51 巻 4 号 p. 234-237
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーThe films colored by a three-step electrolytic coloring method were examined with respect to influence of ultraviolet irradiation using transmission electron microscopy (TEM) and color difference measurement, and the results were compared with those of films colored by a two-step electrolytic coloring method. The three-step electrolyitic coloring films were discolored by the ultraviolet application from a ultraviolet irradiator. TEM observation revealed that the ultraviolet irradiation little affected the thickness of the barrier layer or uniform electrodeposit layer in an AC anodic oxide film. This indicates that the change of the optical path length producing the chromatic color did not result. The results of measurement using a color difference meter indicate an increase of reflected light and a slight hue change from the short-wavelength side to the long-wavelength side (a gray tinged blue to a little light gray). This change of the color tone was attributed not to a change in the path length difference, but rather to a change in the optical intensity difference suitable for interference.抄録全体を表示PDF形式でダウンロード (403K) -
吉原 伸二, 平野 正和, 江藤 武比古2001 年 51 巻 4 号 p. 238-241
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーEffect of Si particles on chipping characteristics of 6061 aluminum alloys during drilling operations has been studied. The formation of fine chips was promoted when more than 2 mass%Si was contained in the above alloys. The number of chips per unit weight, a parameter of chip breaking characteristics, was inversely proportional to the square root of the spacing of Si particles. The mechanism of fine chip formation is as follows through the microscopic observation on the cross section of the chips. The plastic strain is introduced around hard Si particles due to cutting force during the chip formation. The internal stress comes out in Si particles to go critical value. Finally, the cracked Si particles promote the crack propagation across the chips to form fine ones during drilling.抄録全体を表示PDF形式でダウンロード (409K) -
古俣 和直, 鈴木 孝司, 小林 淳哉, 世利 修美2001 年 51 巻 4 号 p. 242-245
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーThe aluminum kettles used in Noboribetsu in Hokkaido leaked in around one year or so. The leakage was caused by corrosion attacks at the bottom of the kettle. The characteristics of corrosion behavior were investigated by SEM, EPMA and electrochemical measurements. The EPMA analysis showed that some ions such as silicate, calcium and sulfate ions dissolved in tap water deposited on the anodized film. The deposited water glass with various contents of silicon and calcium elements causes cracks in the anodized film, which makes the adherence between anodized layer and aluminum substrate weaker and more brittle. The electrochemical measurement reveals that as the temperature becomes higher and concentration of the dissolved ions increases, the anodic polarization resistance of aluminum becomes lower.抄録全体を表示PDF形式でダウンロード (451K)
訂正
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2001 年 51 巻 4 号 p. E2
発行日: 2001年
公開日: 2009/02/17
ジャーナル フリーPDF形式でダウンロード (25K)
解説
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Javier LLORCA, 小林 俊郎2001 年 51 巻 4 号 p. 246-252
発行日: 2001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 (681K)
連載講座
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本城 恒, 松村 英夫, 森田 進一, 三代川 勝2001 年 51 巻 4 号 p. 253-261
発行日: 2001/04/30
公開日: 2021/06/30
ジャーナル フリーPDF形式でダウンロード (2553K)
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