Fatigue Crack Growth Behaviour of 6013 Aluminium Alloy at Different Ageing Conditions in Two Orientations

Authors: AZİZ EGEMEN VARLI, RIZA GÜRBÜZ

Abstract: The effect of different ageing treatments on the fatigue crack growth behaviour of AA6013 aluminium alloy was investigated. C(T) (Compact Tension) specimens prepared in L-T and T-L orientations were aged under 3 different conditions: T651-peak aged (as received), T42-natural aged (solution heat treated at 538 °C for 90 min, water quenched and aged at room temperature for 96 h), and overaged (T42 temper + overageing at 245 °C for 12 h). Electrical conductivity and hardness measurements were performed to verify the heat treatments. Fatigue crack growth tests were performed on the samples with a stress ratio of R = 0.1 and a frequency of 4 Hz. In the T-L orientation, the highest fatigue crack growth resistance was achieved for T651 temper. In the L-T orientation, however, T42 + overageing temper exhibited the highest fatigue performance.

Keywords: Fatigue, Crack growth rate, Aluminium alloy, Ageing, AA6013

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