Effect of Rolling Temperature on the Microstructures and Mechanical Properties of Mg97Zn1Y2 Magnesium Alloy

Mg97Zn1Y2 magnesium alloy was hot-rolled at different temperatures from 390 to 480 A degrees C; the effect of rolling temperature on microstructure evolution and mechanical properties of Mg97Zn1Y2 magnesium alloy was investigated using x-ray diffraction (XRD), laser optical microscopy (LOP), transmission electron microscopy (TEM), and tensile test. The results showed that in the multipass process, the rolling temperature had significant effect on the microstructures and tensile properties for the hot-rolled Mg97Zn1Y alloy. As the rolling temperature was increased, the original strengthening phase-Mg12YZn in as-cast Mg97Zn1Y2 alloy experienced an evolution from dissolution to precipitation, i.e. from chain-shaped Mg12YZn phase together with a little lamellar structure at 420 A degrees C to a maximum volume fraction of lamellar structure at 450 A degrees C, and finally to a reduced volume fraction of lamellar structure at 480 A degrees C. For Mg97Zn1Y2 alloy hot-rolled in the temperature range of 390-450 A degrees C, the tensile strength was at a high level with yielded strength of about 300 MPa and ultimate strength of about 320 MPa. The highest yielded strength was 317 MPa after hot-rolling at 450 A degrees C; the elongation was the highest up to 5.5% after hot-rolling at 420 A degrees C.