Effect of Zn content on the microstructures, mechanical properties, and damping capacities of Mg-7Gd-3Y-1Nd-0.5Zr based alloys

The microstructures, mechanical properties, and damping capacities of the Mg-7Gd-3Y-1Nd-0.5Zr based alloys with 0.5, 1, 2 wt% Zn addition were investigated systematically in the present study. The results show that increasing Zn content led to the decrease in the number of dynamic recrystallization grains and the number of deformed grain gradually increased in the as-extruded alloys. Subsequent ageing heat treatment revealed that precipitation strengthening was reduced and the hardness decreased with increasing Zn. Tensile tests of the as-extruded alloys at room temperature suggested that Zn addition notably increased the strengths while maintaining high elongation. In the peak-aged alloys, the strengths decreased and the elongation increased with increasing Zn. At 300 degrees C, the 14H-LPSO phases enhanced the damping capacities within the whole strain range. The dislocation and grain boundary damping peaks were found in the damping temperature spectra of the three kinds of alloys. With enhanced Zn content, the grain boundary damping peak was weakened. (C) 2018 Elsevier B.V. All rights reserved.