【摘要】 研究了ZK31+xYb合金中Yb的分布及作用。结果表明:Zn和Yb能相互降低对方在镁合金中的溶解度,少量(1 0%)的Yb加入ZK31合金中,Zn与Yb的分布都较均匀,在凝固过程中优先形成Yb Zn金属间化合物,提高Yb含量(2 0%),Yb向晶界偏聚,并促使Zn向晶界偏聚,凝固过程中有少量金属间化合物Mg2Zn2Yb先于α Mg形成,大部分的Yb和Zn在凝固后期形成金属间化合物Mg15Zn2Yb,进一步提高Yb的含量,固溶以外的Yb和Zn均向晶界偏聚,在凝固后期形成金属间化合物Mg15Zn2Yb和Mg10Zn3Yb2。此外,Yb元素能有效细化ZK31镁合金的晶粒。更多还原

【Abstract】 The distribution and role of Yb in the magnesium alloy ZK31+xYb were studied.The result shows: Zn and Yb can decrease the solubility in magnesium each other.With small quantity addition of Yb（1.0%）,both Zn and Yb distribute homogenously in the ZK31 magnesium alloy,and Yb-Zn binary intermetallics formed prior to α-Mg during solidification.Increasing of Yb addition,Yb began to segregate to grain boundary,and it can promote the segregation of Zn,a small amount of Mg-Zn-Yb ternary intermetallics Mg₂Zn₂Yb formed prior to α-Mg during solidification,but most of the Yb and Zn formed ternary intermetallics Mg₁₅Zn₂Yb in the lateral stage of solidification.With further increasing of Yb addition,most of the Yb and Zn segregated to the grain boundary to form ternary intermetallics Mg₁₅Zn₂Yb and Mg₁₀Zn₃Yb₂ except the soluted ones.Moreover,Yb can obviously refine the grain of magnesium alloy ZK31.更多还原