轧制及退火态的Mg-Y-Zr-xNd合金的组织和力学性能（英文）

Microstructure and Mechanical Properties of Rolled and Annealed Mg-Y-Zr-xNd Alloys

通过OM、SEM、XRD、EBSD和拉伸试验研究了不同热处理条件下Mg-5Y-0.6Zr-x Nd(x=0,0.5%,1%,质量分数)合金的组织和力学性能。结果表明,随着Nd含量的增加,第二相Mg24Y5和Mg14Nd2Y(β)在基体中的含量增加。添加少量Nd可以降低α-Mg的堆垛层错能,促进热轧过程中的动态再结晶。随着Nd含量的增加,静态再结晶的体积分数明显增加。退火处理后Mg-5Y-0.6Zr-0Nd合金的平均晶粒可细化至3.73μm。轧制合金的抗拉强度随着Nd的增加而增加,而伸长率则表现出相反的变化趋势。含有1.01%Nd的轧制合金具有优良的机械性能,其抗拉强度、屈服强度和伸长率分别为336 MPa、278 MPa和16.3%。在微观结构观察的基础上,讨论了力学性能的变化。

Microstructures and mechanical properties of Mg-5Y-0.6Zr-xNd(x=0,0.5 and 1wt%)alloys under various heat treatment conditions were investigated by optical microstructure(OM),scanning electron microscope(SEM),X-ray diffraction(XRD),electron backscatter diffraction(EBSD)and tensile tests.The results show that with the increase Nd of content,the amount of second phases Mg24Y5 and Mg14Nd2Y(β)increases in the matrix.Minor Nd addition can reduce the stacking fault energy ofα-Mg and promote the dynamic recrystallization during hot-rolled process.As the Nd content increases,the volume fraction of static recrystallization is promoted obviously.The average grain size of Mg-5Y-0.6Zr-0Nd alloy after annealing treatment can be refined to 3.73μm.Tensile strength of as-rolled alloys increases with the addition of Nd,while the elongation decreases.As-rolled alloy sheet with 1.01 wt%Nd exhibits remarkable mechanical properties,in which the values of ultimate tensile strength,yield strength and elongation are 336MPa,278 MPa and 16.3%,respectively.Based on the microstructure observation,the changes of mechanical properties were discussed.