Effect of Solid Solution Treatment on Microstructure and Mechanical Properties of Mg97Y2Zn1 Alloy

The X-phase grew in the matrix on the basal plane (0001) when Mg97Y2Zn1 alloy was solution treated at 415 and 540 degrees C. However, increasing the treatment temperature up to 560 degrees C, some X-phases may be dissolved. It was further observed that the dynamic recrystallization (DRX) process was completed and abnormal grain growth in the extruded alloy that was solution treated at 415 degrees C. On the other hand, the incomplete DRX process in the alloy treated at 560 degrees C was restrained by high content of induced yttrium in matrix. The Mg97Y2Zn1 alloys treated in the range of 415-560 degrees C exhibit excellent mechanical properties, among which the highest strength was obtained in the one treated at 560 degrees C. The high strength is believed to be owing to the ultra-fine grain, high density of plane faults of the long-period stacking structures, strain strengthening, and solid solution strengthening.