Effects of phase composition on the mechanical properties and damping capacities of as-extruded Mg-Zn-Y-Zr alloys

The present work mainly investigated the microstructures, mechanical properties, and damping capacities of as-extruded Mg-Zn-Y-Zr alloys with varied phase composition. Alloys of MgZn(2), W-phases (Mg(3)Y(2)Zn(3)), I-phases (Mg(3)YZn(6)), and X-phases (Mg(12)YZn) were obtained by adjusting the Zn/Y ratio (in wt%). The crystallographic structure of the X-phase [long period stacking ordered (LPSO) phase] and the crystallographic relationship between the W-phase and the Mg matrix were determined. The strengthening effects of the phase composition on the alloys exhibited the following trend: W + LPSO > LPSO>W + I > MgZn(2). Variations in the phase composition resulted in almost consistent variations in the damping capacities of the alloys compared with their mechanical properties. The LPSO structural phase could enhance the mechanical properties and simultaneously maintain the good damping capacity of the alloys. (C) 2011 Elsevier B.V. All rights reserved.