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在碳管炉中熔炼制备不同Zr含量的Fe-36Ni因瓦合金,并通过SEM和EDS等手段研究了添加Zr及凝固条件对合金凝固组织的影响,并分析了凝固组织改善的机理。结果表明:添加Zr的合金凝固组织得到显著细化,且随着Zr含量的增加,凝固组织的细化效果变好。添加Zr后,合金中形成了大量弥散分布的高熔点化合物ZrO2,而ZrO2(0001)面与合金基体(100)面的错配度较低,故ZrO2可作为合金凝固过程中有效的非均质形核核心,细化合金的凝固组织。在添加相同含量稀土Y的条件下,随着浇铸温度的降低和冷却速度的增大,凝固组织明显细化;当浇铸温度超过1 500℃后,Y2O2S作为非均质形核核心的作用消失,合金凝固组织为完全的柱状晶组织。
The effects of adding Zr and solidification conditions on the solidification microstructure of the alloy were studied by means of SEM and EDS. The mechanism of the solidification microstructure was analyzed. The results show that the solidified microstructure of Zr-rich alloy is remarkably refined. With the increase of Zr content, the refining effect of solidified structure becomes better. After adding Zr, a large amount of high-melting compound ZrO2 is formed in the alloy, and the misorientation between the ZrO2 (0001) plane and the alloy matrix (100) surface is low, so ZrO2 can be used as the effective heterogeneity in solidification of the alloy Core nucleation, refinement of alloy solidification organization. With the addition of the same amount of rare earth Y, the solidified microstructure is obviously refined with the decrease of the casting temperature and the cooling rate. When the casting temperature exceeds 1500 ℃, the role of Y2O2S as the heterogeneous nucleation center disappears, Alloy solidification organization for the complete columnar crystal structure.