7Zn3轉(zhuǎn)變?yōu)镸g3Zn3Y2，最終轉(zhuǎn)變?yōu)镸g12ZnY。Y元素的加入阻礙了動態(tài)再結(jié)晶的生長過程，使晶粒得到細化，但是進一步增加Y含量不會繼續(xù)增強晶粒細化程度。擠壓態(tài)Mg-2Zn-1Mn合金加入Y元素后，塑性呈現(xiàn)出先升高后下降的趨勢，這可能是受到了織構(gòu)取向變化和晶粒粗化的共同影響。此外，合金強度提高主要是由于細晶強化和第二相強化作用。Mg-2Zn-1Mn-7Y合金具有最佳的力學(xué)性能，其抗拉伸強度為357 MPa，屈服強度為262 MPa，延伸率為14%。;The microstructure and mechanical properties of Mg-2Zn-1Mn-xY (x=0, 1, 3, 5, 7, wt%) alloy were studied by optical microscope (OM), X-ray diffractometer (XRD), X-ray fluorescence spectrometer (XRF), electron probe microanalyzer (EPMA), scanning electron microscope (SEM), electron backscatter diffractometer (EBSD), transmission electron microscope (TEM), and uniaxial tensile tests. Results show that the secondary phases of as-cast alloys are changed from Mg7Zn3 to Mg3Zn3Y2 and finally transformed to Mg12ZnY with the addition of Y element. Although Y addition hinders the dynamic recrystallization process and therefore refines the grains, the excess Y addition cannot further refine the grains. Meanwhile, the ductility of as-extruded Mg-2Zn-1Mn alloy is increased and then decreased with the addition of Y element, which may be attributed to the synergistic effect of texture orientation and grain coarsening. Besides, the strength enhancement is mainly attributed to grain refinement strengthening and secondary phase strengthening. The Mg-2Zn-1Mn-7Y alloy has the optimal mechanical properties: the ultimate tensile strength is 357 MPa, yield strength is 262 MPa, and elongation is 14%."/>