Effect of heat treatment and pre-deformation on damping capacity of cast Mg-Y binary alloys

Abstract

The damping capacity (Q−1) of cast Mg-xY (x = 1, 3, 7 wt%) binary alloys were studied in aspects of yttrium (Y) content, heat treatment and pre-deformation. The relationship between amplitude and Q−1 fitted well with the G-L dislocation damping model for all the studied alloys. With Y content increasing from 1% to 7%, the Q−1 significantly decreased from 0.15 to 0.002 in the strain range of 10−6∼10−3, while the yield strength increased from 20 ± 2 MPa to 92 ± 4 MPa. The solid solution heat treatment (T4, 793 K × 6 h) markedly improved the Q−1, because the movement of dislocations was impeded by more Y solute atoms as weak pinning points. The 25% pre-deformation reduced the Q−1 value of T4 treated Mg-1Y alloys by half, which may result from the increased dislocation density due to work hardening and the decreased stacking fault energy by the Y addition. Moreover, both the pre-deformation and increasing Y content extended the critical strain amplitude εc. The Mg-Y alloys exhibited promising potential for developing high-performance damping alloys based on comparing with several Mg-based damping alloys in terms of both damping capacity and strength.