부산대학교 도서관

This article investigated the effect of Mg content (4.5, 6.5 and 9.2, in wt%) on the damping capacities of Al–Mg alloys. The results indicate that the damping behavior can be divided into three regions. Region I refers to the low strain amplituderegion (ε < 5 × 10−5), where the damping capacity decreases with increasing the Mg content and has almost no relation withthe strain amplitude. Region II is the middle strain amplitude region (5 × 10−5 < ε < 8 × 10−4), where the damping capacityincreases rapidly with the strain. Region III refers to the high strain amplitude region (8 × 10−4 < ε < 2 × 10−3), where thedamping capacity remains constant and is independent of the strain when the strain is high enough, but increases with the Mgcontent. The damping values Q−1 of Al–4.5Mg, Al–6.5Mg and Al–9.2Mg alloys are 0.01501 ± 0.00032, 0.01633 ± 0.00032and 0.01862 ± 0.00119 at the strain of 1 × 10−3, respectively. The damping capacity in Region I is mainly determined bythe lattice distortion caused by Mg addition and the restoring force caused by pinning points and Suzuki segregation. Theextended dislocations break away from the pinning effect of Mg atoms and become moveable in Region II, and the movementof extended dislocations is the dominant damping mechanism in Region III.