稀土镨对金属间化合物Mg2Si组织的影响

为了改善金属间化合物Mg₂Si在常温下的组织形态与分布，采用在Al₃₀Mg₂Si合金中添加不同量稀土元素镨（Pr）的办法，研究Pr对该合金中Mg₂Si变质的影响.结果表明：适量的稀土元素Pr能够明显细化Mg₂Si晶粒，改善其形态及其分布.当Pr加入0.2%时能够抑制Mg₂Si树枝晶生长，且能使Mg₂Si相均匀分布.当Pr加入0.6%~0.8%时，Mg₂Si相呈规则多边体形态，且分布更加均匀，组织更加细小，可认为该含量时Mg₂Si组织最完善，稀土Pr变质效果最好.当Pr增加到1.7%时，Mg₂Si相再次呈不规则状，且分布不均匀.

Effect of praseodymium on microstructure of intermetallic compound Mg2Si

In order to improve the microstructural morphology and distribution of intermetallic compound Mg₂Si at room temperature, different content of rare earth element Pr was added into the Al₃₀Mg₂Si alloy. The influence of Pr on the Mg₂Si modification in the alloy was studied. The results showed that an appropriate amount of Pr can significantly refine Mg₂Si phase and improve the morphology and distribution of Mg₂Si phase. The dendritic growth of Mg₂Si phase can be inhibited and the distribution of Mg₂Si phase is more uniform with the addition of 0.2% Pr. When the addition amount of Pr is 0.6% to 0.8%, the morphology of Mg₂Si phase is regular polygonal, its distribution becomes much more uniform, and themicrostructure is much finer. And thus, the optimal modification effect of Pr is attained. When the addition amount of Pr increases to 1.7%, the morphology of Mg₂Si phase becomes irregular and its distribution is uneven.