A7079-T6高強度アルミニウム合金のき裂伝ぱに及ぼす繰り返し速度の影響 : 第1報 : 大気中と真空中での比較

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キーワード : アルミニウム合金 A7079-T6 疲労き裂伝ぱ繰り返し速度腐食疲労　抄録 : Experiments were conducted to study the effect of air and vacuum environments on the number of cycles to failure of the A7079-T6 High-Strength Aluminum Alloy, at 2Hz and 0.02Hz cyclic-load frequency. Althouth the test results in air scattered widely more than those in vacuum, the number of cycles to failure was smaller in air than in vacuum. Similarly, the number was smaller at 0.02Hz than at 2Hz. The slope of the line in da/dn-ΔK graph increased at AK≒18 MPa√<m>. Below that value, slow loading rates accelerate the crack growth, but beyond that value, the effect of cyclic-load frequency was negligibly small. Within the scope of these experiments, the magnitude of the effect of air environment on the fatigue-crack growth rate was larger than that of cyclic-load frequency. Besides, the effect of air envionment was observed in all the range of ΔK, though the effect decreased gradually as ΔK increased. These behaviors seemed to be caused with corrosion-fatigue, therefore, effects of loading variables such as cyclic-load frequency will be explained more clearly by the test-results in vacuum. Results in air showed the combined effects of environments such as air, with time-dependent loading variables such as cyclic-load frequency.
鶴岡工業高等専門学校の論文
2004-12-20