Y含量对Mg-Zn-Y合金组织和性能的影响

Effects of Yttrium on Microstructure and Mechanical Properties of Mg-Zn-Y Alloys

采用X射线衍射和金相显微分析研究了元素Y对Mg-3Zn-xY(x=0.5、1.5、3.0、6.0,质量分数/%)合金显微组织和力学性能的影响。结果表明,在基体中和晶界分布的弥散质点随Y含量的增加而增多,尺寸增大。合金中二次相的种类取决于w(Zn)/w(Y)之比值,随着Y含量的增加,合金中的二次相依次从Mg7Zn3相+I相、I相+W相到W相+H相、H相转变,晶间组织的形态也由点状、细线状向网状转变。合金的抗拉强度、硬度、冲击韧度随着Y含量的增加而提高,塑性则逐渐下降。但Y含量达到6%时合金的综合力学性能下降。

Effects of yttrium on microstructure and mechanical properties of Mg-3Zn-xY(x=0.5,1.5,3,6)alloys were investigated by X-ray and microscope.The results show that the size and amounts of particles in the matrix and at grain boundary are increased with increasing yttrium content.The type of second phase in the alloy is found to be dependent upon the Zn/Y ratio.With the Y content increases,the second phase is converted from Mg_7Zn_3 +I phase to I phase +W phase,and to W phase +H phase to H phase.The shapes of the second phases at the grain boundaries are transformed from punctate to short rodlike,and to reticular particles.The tensile strength,hardness and impacting toughness of alloy are improved while the plasticity is decreased with Y content increasing.However,the comprehensive mechanical properties are descended with 6% Y addition.