摘要
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 invar alloy was investigated. The results show that the solidification structure of the alloy is well improved. The equiaxed grain ratio in solidification structure increases, the equiaxed grain size decreases, the dendrite becomes thinner and shorter, the primary dendrite arm spacing decreases, the secondary dendrite ann spacing unchangs with the increase of La content. An amount of high-melting compounds （La2O2S） with a size of 4μm form in the alloy because of La addition. Based on the theory of lattice misfit, the lattice misfit between low-index surface of Fe-36Ni invar alloy and low-index surface of La2O2S is only 5.42%, which is relatively low. As a result, La2O2S can serve as the core of heterogeneous nucleation, improve nucleation ratio and refine solidification structure of the alloy.
出处
《铸造技术》
CAS
北大核心
2012年第3期270-273,共4页
Foundry Technology
