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研究了La对Fe-36Ni低膨胀合金凝固组织的影响。结果表明,加La处理后,合金的凝固组织得到显著改善,随着合金中La含量的增加,凝固组织的等轴晶比例增加,等轴晶尺寸减小,树枝晶变细变短,一次枝晶间距减小,二次枝晶间距基本不变。经La处理后,Fe-36Ni低膨胀合金中形成了大量高熔点的La2O2S颗粒,尺寸约为4μm。错配度计算表明,Fe-36Ni低膨胀合金的低指数面与La2O2S的低指数面有5.42%的较低错配度,因此La2O2S可以作为有效的非均质形核的核心,提高形核率,细化合金的凝固组织。
The effect of La on the solidification structure of Fe-36Ni low expansion alloy was studied. The results show that the solidification microstructure of the alloy is improved obviously with the addition of La. With the increase of La content in the alloy, the proportion of equiaxed grains in the solidified structure increases and the equiaxed grains decrease in size. Intergranular spacing is reduced, the secondary dendrite spacing is basically unchanged. After La treatment, Fe-36Ni low expansion alloy formed a large number of high melting point La2O2S particles, the size of about 4μm. The mismatch calculation shows that the low index surface of Fe-36Ni low-expansion alloy has a 5.42% mismatch with the low index surface of La 2 O 2 S, so La 2 O 2 S can serve as the core of effective heterogeneous nucleation and improve the nucleation rate , Refine the solidification of the alloy.