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<p>To improve element segregation and solidification microstructure in the GH4169 superalloy, this study investigated the microstructure, eutectic carbides, Laves phase, and elemental microsegregation in electroslag remelting (ESR) ingots with different La contents. The results showed that, when the La content increased from 0 to 0.043&#xa0;wt.%, the solidification onset temperature rose from 1333°C to 1341°C, while the solidification termination temperature increased from 1178°C to 1189°C. The secondary dendrite arm spacing at the ingot center decreased from 68.7&#xa0;μm to 63.1&#xa0;μm, and the area fractions of NbC and Laves phase in the as-cast structure decreased by 20.59% and 22.22%, respectively. Nb exhibited the most severe microsegregation in the GH4169 alloy, followed by Mo. With La content increasing from 0 to 0.043&#xa0;wt.%, the microsegregation indices of Nb, Mo, Cr, Fe, and Ni decreased. At the early stage of the solidification process, La-containing inclusions acted as heterogeneous nucleation sites, increasing the nucleation rate. At the late stage of solidification, dissolved La atoms in the liquid metal enriched at the front of solid–liquid interface, enhancing constitutional supercooling and restricting dendrite growth.</p>

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Effects of Lanthanum on the Solidification Structure and Precipitation of GH4169 Superalloy by Electroslag Remelting

  • 期刊论文

  • 发表日期：

    2025年11月26日

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  • Fuli Zhang,
  • Dingli Zheng,
  • Yufei Wang,
  • Zibing Hou,
  • Ruihua Guo,
  • Chao Ma,
  • Yi Liu

摘要

To improve element segregation and solidification microstructure in the GH4169 superalloy, this study investigated the microstructure, eutectic carbides, Laves phase, and elemental microsegregation in electroslag remelting (ESR) ingots with different La contents. The results showed that, when the La content increased from 0 to 0.043 wt.%, the solidification onset temperature rose from 1333°C to 1341°C, while the solidification termination temperature increased from 1178°C to 1189°C. The secondary dendrite arm spacing at the ingot center decreased from 68.7 μm to 63.1 μm, and the area fractions of NbC and Laves phase in the as-cast structure decreased by 20.59% and 22.22%, respectively. Nb exhibited the most severe microsegregation in the GH4169 alloy, followed by Mo. With La content increasing from 0 to 0.043 wt.%, the microsegregation indices of Nb, Mo, Cr, Fe, and Ni decreased. At the early stage of the solidification process, La-containing inclusions acted as heterogeneous nucleation sites, increasing the nucleation rate. At the late stage of solidification, dissolved La atoms in the liquid metal enriched at the front of solid–liquid interface, enhancing constitutional supercooling and restricting dendrite growth.