@article{oai:jaxa.repo.nii.ac.jp:00032214,
 author = {堀内, 良 and 斎藤, 敏 and 岸, 輝雄 and HORIUCHI, Ryo and SAITO, Satoshi and KISHI, Teruo},
 issue = {3_B},
 journal = {東京大学宇宙航空研究所報告},
 month = {Sep},
 note = {アルミニウム合金について,引張り-圧縮による低サイクル疲労試験を行なった.試料は市販純アルミニウム(2S)Al-Mg合金(56S),Al-Cu-Mg合金(24S)で,繰返し引張り-圧縮試験の応力-ひずみ曲線からバウシンガー効果,疲労硬化について検討し,疲労組織の透過電顕観察を行なった.おもな結果は次のごとくであった.(1)バウシンガー効果による降伏応力の低下σ_Bと予ひずみεの間には,五弓,岸がねじり試験で求めた.σ_B= k^m(k,mは定数)の関数が軸方向力の場合にも成立した.(2)バウシンガー効果は純アルミニウムが一番小さく強度の高い合金では大きくなる.析出硬化型合金ではバウシンガー効果は析出伏態に依存し,過時効状態で最大になる.(3)疲労硬化は塑性ひずみ振幅の大きいほど大きく,純アルミニウムでは塑性ひずみ5%以上の振幅にすると硬化が飽和した後わずかに軟化する.これに対し56S,24Sではひずみ振幅0.3%以上では破断に至るまで硬化は飽和しない.(4)電顕観察では亀裂や空洞は見出せなかったが,純アルミニウムでは松位は鮮鋭なセル壁をつくり,セルの大きさは繰返し数にはほとんど依存しない. 56S,24Sでは転位密度は小さな塑性ひずみでいちじるしく増大し,ほぼ全面に均一に分布するが,繰返し数が増すと転位密度の高い部分と低い部分の規則的なまだら模様となる., A study of low cycle fatigue under the axial load was carried out on 2S, 24S, 56S and 63S aluminum alloys. Particular attention, was paid to the cyclic hardening behavior and the fatigued structure observed by the transmission electron microscopy. The obtained results are summarized as follows : (1) It was found in the axial tension-compression test that the relation between OB, the yield stress drop due to the Bauschinger effect and the amount of prestrain, can be expressed by the equation, σ_B = ε^m, where k and m are constants. This experimental equation was first obtained by Gokyu and Kishi in the cyclic torsion test. (2) The Bauschinger effect in 2S commercial pure aluminum was the smallest and generally this effect was larger in its alloys. In precipitation hardening alloys, the Bauschinger effect changed, depending on the ageing conditions and was the largest in the overaged specimens. (3) For the larger plastic strain amplitude, the fatigue hardening was more pronounced and the total plastic strain for saturation in cyclic hardening increased. In pure aluminum, slight cyclic softening was observed for the plastic strain amplitude more than 5%. In the case of 56S and 24S, however, saturation in hardening was not observed for the plastic strain amplitude more than 0.3%. The amount of hardening for the initial straining direction was greater than that for the reverse direction. (4) It was observed by the transmission electron microscopy that the dislocation structure of cyclic strained pure aluminum is made up of tangled cell walls, and cell size is almost indepent of the cycle number. On the contrary, in the case of 24S and 56S, dislocation density increases rapidly in the small strain region (about 1%) and rather homogeneous distribution of dislocations was observed. When the total plastic strain approaches to the region of saturation in cyclic hardening, the mottled structure was observed which consists of the high and low dislocation density portions., 資料番号: SA0125366000},
 pages = {748--762},
 title = {アルミニウム合金の低サイクル疲労における疲労硬化と疲労組織の電顕観察},
 volume = {6},
 year = {1970}
}