Effects of Y content and temperature on the damping capacity of extruded Mg-Y sheets

The damping behavior of extruded Mg-xY (x = 0.5, 1.0, 3.0 wt.%) sheets were investigated in detail concerning the effects of Y addition and temperature, and the relationship between damping capacity and yield strength was discussed. At room temperature (RT), with Y content increasing from 0.5% to 3.0%, the damping capacity (Q(-1)) significantly decreased from 0.037 to 0.015. For all the studied sheets, the relationship between strain amplitude and Q(-1) fitted well with the Granato and Lucke (G-L) dislocation damping model. With temperature increased, the G-L plots deviated from linearity indicating that the dislocation damping was not the only dominate mechanism, and the grain boundary sliding (GBS) could contribute to damping capacity. Consequently, the Q(-1) increased remarkably above the critical temperature, and the critical temperature increased significantly from 50 degrees C to 290 degrees C with increasing Y contents from 0 to 3.0 wt.%. This result implied that the segregation of Y solutes at grain boundary could depress the GBS, which was consistent with the recent finding of segregation tendency for rare-earth solutes. The extruded Mg-1Y sheet exhibited slightly higher yield strength (R-p(0.)2) and Q(-1) comparing with high-damping Mg-0.6Zr at RT. At an elevated temperature of 325 degrees C, the Mg-1Y sheet had similar Q(-1) but over 3 times larger R-p0.2 than that of the pure Mg. The present study indicated that the extruded Mg-Y based alloys exhibited promising potential for developing high-performance damping alloys, especially for the elevated-temperature application. (C) 2019 Published by Elsevier B.V. on behalf of Chongqing University.