Study on Improving Damping Capacity of Pure Magnesium by Ultrasonic Impact Treatment
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JMEPEG https://doi.org/10.1007/s11665-020-05249-z
Study on Improving Damping Capacity of Pure Magnesium by Ultrasonic Impact Treatment Diqing Wan, Jiajun Hu, Yinglin Hu, Houbin Wang, Yandan Xue, and Zhichao Huang Submitted: 29 June 2020 / Revised: 14 September 2020 / Accepted: 27 September 2020 The effect of ultrasonic impact treatment (UIT) on the damping capacity of pure magnesium is revealed in this paper. The results show that after UIT, the metal underwent dynamic plastic deformation, the damping capacity of pure magnesium was greatly improved, however, as the UIT time and current intensity increased, the damping capacity of the impacted samples are decreased. Two internal friction peaks have been obtained in all tested samples, P1 is considered to be related to the interaction between dislocations and weak pinners, and P2 is caused by the grain boundaries sliding. After the UIT process, those internal friction peaks shift to a higher temperature, with the peak height decrease. The change in damping capacity is believed to be related to the increase in dislocation density and the number of vacancies and grain boundaries. Keywords
damping capacity, internal friction, magnesium, ultrasonic impact treatment (UIT)
1. Introduction Damping refers to a phenomenon of vibration energy consumption caused by external or inherent factors in the material during vibration (Ref 1, 2), also as known as internal friction. Damping capacities are one of the three major functional properties in materials (superplasticity, damping capacities, and shape-memory characteristics). A high damping material has excellent shock-absorption and noise-reduction performance, which makes it widely notable. To meet the needs of aviation, aerospace, and modern industrial development, the development of new high damping materials has become a hot research topic (Ref 3, 4). Ultrasonic impact treatment (UIT) is an advanced processing technology that is often used to introduce plastic deformations and beneficial residual compressive stresses at weld seams to improve the fatigue strength and service life of the welded material (Ref 5, 6). Meanwhile, UIT is also an effective surface treatment process (Ref 7) that can improve the wear resistance, corrosion resistance, and other surface properties of the materials, because this process can greatly refine the grain on the materialÕs surface and even reach the nanometer scale (Ref 8). In addition, after UIT, the dislocation density of materials will change obviously due to the severe plastic deformation (Ref 9). The changes in dislocation density and grain size could affect the damping capacities of magnesium-based materials, especially dislocation damping (Ref 10, 11). Unfortunately, most researchers are currently focused on exploring the impact of UIT on materialsÕ fatigue and surface properties, while there Diqing Wan, Jiajun Hu, Yinglin Hu, Houbin Wang, Yandan Xue, and Zhichao Huang, School of Materials Science and Engineering, East China Jiaotong University, Nanchang 330013, China. Contact e-mails:
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