Nonlinear ultrasonic characterization of early degradation of fatigued Al6061-T6 with harmonic generation technique
Nonlinear ultrasonic characterization of early degradation of fatigued Al6061-T6 with harmonic generation technique
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DOI：
10.1016/j.ultras.2017.12.011
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发表时间：
2018-04-01
期刊：
影响因子：
4.2
通讯作者：
Song, Sung-Jin
中科院分区：
文献类型：
--
作者：
Gebrekidan, S. B.;Kang, To;Song, Sung-Jin
本文利用三次谐波研究了不同疲劳循环对Al6061-T6合金微观组织的影响，得到了疲劳循环与三阶非线性的关系。对疲劳循环次数分别为0%、55%、75%和85%的试件分别采用了压电测量谐波产生技术。结果表明，随着疲劳循环次数的增加，三次谐波逐渐增加，最高可达55%，并在疲劳后迅速下降，这归因于位错、位错-析出物相互作用和空洞的行为。并用扫描电子显微镜(SEM)对其进行了验证。我们还观察到，在55%的疲劳寿命后，三阶非线性比二阶非线性对孔洞面积的微小变化更敏感，可以作为研究含孔洞的Al6061-T6试件的一个很好的候选材料。(C)2018爱思唯尔B.V.保留所有权利。
In this paper, a third harmonic was used to investigate microstructural changes in Al6061-T6 due to different fatigue cycles and a relationship between fatigue cycle and third order nonlinearity has been observed. Piezoelectric measurement harmonic generation technique was applied for the specimens with 0%, 55%, 75% and 85% fatigue cycles, respectively. The results shows that the third order harmonics gradually increased up to 55% and rapidly decreased after wards, it was attributed to the behavior of dislocation, dislocation-precipitation interaction and voids with increasing fatigue cycle. Further, it was verified with scanning electron microscope (SEM). We also observed that third order nonlinearity is more sensitive to small change in area of fraction of voids than second order nonlinearity after 55% fatigue life and could be a good candidate to investigate Al6061-T6 specimen with voids. (C) 2018 Elsevier B.V. All rights reserved.