Effects of Y content on microstructure, mechanical and damping properties of Mg–Al–Y alloys

Abstract

The effect of Y on microstructure, mechanical properties, and damping properties of the extruded and annealed Mg–1Al– x Y ( x = 4, 6, 8) alloys has been studied. The grain sizes of Mg–Al–Y alloys decreased with the increase of Y. The mechanical properties of Mg–Al–Y alloys improved with increasing Y content. The temperature-dependent damping spectrum could be divided into three parts. The vibration frequency weakly affects the damping capacity of Mg alloys. The result of temperature-dependent damping capacity indicated that the overall trends of the tan ϕ decreased at first and then increased with the Y Mg–Al–Y alloys at temperatures between 300 K to 675 K. There were two temperature damping peaks P _1 and P _2 , which was caused by grain boundary relaxation and grain boundary slip, respectively. Grain boundary slip can significantly affect the damping capacity of the Mg alloys at high temperature. The results of XRD showed that the residual stresses existed in the Mg–1Al– x Y ( x = 4, 6, 8) alloys after the damping test, which was consistent with the results of damping performance test.

Keywords

• microstructure
• grain sizes
• damping peaks
• grain boundary slip
• residual stresses