A study of high damping capacities and mechanical properties of cast Mg-Gd binary alloys

Abstract

In this study, we aim at the inherent contradiction that the addition of elements with strong solid solubility strengthening effect in Mg leads to a sharp deterioration of damping capacities. It is proposed that utilizing the element with the low growth restrict factor (GRF) can form parallel distribution of second phases in solidification microstructure to impede the sharp deterioration of damping capacities with increasing element content. In cast Mg-xGd (x = 1, 1.5, 3, 6 wt%) binary alloys, with increasing Gd (GRF = 1.03) content from 1 wt% to 6 wt%, the damping value Q−1 decreases from 0.16 to 0.05 due to the existence of the parallel distribution of second phases at the strain amplitude of 0.8 × 10−3, while the yield strength increases 30 MPa to 84 MPa. Compared with the reported sharp decrease in damping properties of high-damping Mg-Y alloys with increasing Y content, Mg-Gd alloys could be promising potential candidates for developing high-performance damping magnesium alloys (Q−1 ≥ 0.01).