【摘要】 采用金属型铸造法制备了Mg-3.2Nd-0.5Zn-0.4Zr、Mg-3.2Nd-0.5Zn-0.4Zr-0.4Y和Mg-3.2Nd-0.5Zn-0.4Zr-0.4Gd合金，研究了Gd、Y元素微合金化对Mg-Nd-Zn-Zr合金组织与性能的影响。结果表明：铸态合金主要由α-Mg及Mg₁₂Nd相组成，经540℃×8 h固溶处理后，Mg₁₂Nd相溶入基体或转变为Mg₄₁Nd₅相。Gd、Y元素的添加均促进Mg₁₂Nd相向Mg₄₁Nd₅相的转变，且与添加Y元素相比，添加Gd元素后转变的相数量更多且相形态更为平滑。铸态下添加Gd、Y元素的合金较基体合金伸长率提升了35.6%和64.4%,经540℃×8 h固溶处理及200℃×105 min时效处理后，添加Gd元素的合金综合力学性能更好，伸长率提升了30.3%,且Gd元素更易促进Mg₁₂Nd相向Mg₄₁Nd₅相转变，从而使合金表现出更高的伸长率，更有利于合金之后的加工变形。更多还原

【Abstract】 Mg-3.2Nd-0.5Zn-0.4Zr, Mg-3.2Nd-0.5Zn-0.4Zr-0.4Y and Mg-3.2Nd-0.5Zn-0.4Zr-0.4Gd alloys were prepared by the permanent mold casting method. The effects of Gd and Y microalloying on the microstructure and properties of Mg-Nd-Zn-Zr alloys were investigated. The results show that the as-cast alloys are mainly composed of α-Mg and Mg₁₂Nd phases. After solution treatment at 540 ℃ for 8 h, the Mg₁₂Nd phase dissolves into the matrix or transforms into Mg₄₁Nd₅ phase. The addition of Gd and Y elements both promotes the transformation of Mg₁₂Nd phase to Mg₄₁Nd₅ phase. The addition of Gd induces more phase transformation and a smoother phase morphology compared with that of Y. The addition of Gd and Y elements in the as-cast state increases the elongation of the base alloy by 35.6% and 64.4%, respectively. After solution treatment at 540 ℃ for 8 h and aging treatment at 200 ℃ for 105 min, the alloy with Gd addition exhibits better comprehensive mechanical properties and a 30.3% increase in elongation. Gd element is more effective in promoting the transformation of Mg₁₂Nd phase to Mg₄₁Nd₅ phase, thereby enabling the alloy to exhibit higher elongation and more conducive to subsequent processing deformation.更多还原