ECAE法により作製した5056アルミニウム合金の高サイクル疲労特性 [in Japanese] High cycle fatigue properties of 5056 aluminum alloy produced by Equal-Channel Angular Extrusion [in Japanese]
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The fatigue behavior of the fine-grained 5056 aluminum alloy produced by equal-channel angular extrusion (ECAE) is explored. This material exhibits a slightly enhanced fatigue life at high stress amplitude. However, no improvement in the fatigue limit is observed. Fatigue performance is discussed in terms of fatigue life, crack nucleation and propagation. Structural change during fatigue test is investigated by transmission electron microscopy and DSC. It is shown that the fine structure achieved during processing is unstable and tends to relax with cycling, resulting in local recovery of the pre-deformed material. Structure relaxation during fatigue test is supposed to provoke notable cyclic softening that is particularly pronounced at higher applied stress. It is found that the crack growth rate is greater in the fine grain ECAE material than in the coarse grain counterpart. The improvement of fatigue properties at low-cycle regime is believed to be due to higher resistance to crack nucleation in the fine-grained material having a larger proof stress value.
- Journal of Japan Institute of Light Metals
Journal of Japan Institute of Light Metals 51(6), 324-328, 2001-06-30
The Japan Institute of Light Metals