The influence of Ce addition on the solidification structure and σ phase of super austenitic stainless steel S32654 was systematically investigated via microstructural characterization and thermodynamic calcula-tion.The results indicate that a small addition of Ce could modify MgO and MnS into Ce-bearing inclu-sions Ce2O3 and Ce2O2S.Ce addition led to noticeable refinement of both the dendrite structure and σphase.The refinement mechanism could be attributed to the combined actions of effective Ce-bearing inclusions and solute Ce.Effective Ce-bearing inclusions could serve as heterogeneous nucleation cores of austenite as well as σ phase,which provided a favorable prerequisite for their refinement.Solute Ce significantly enhanced the undercooling degree of the system,further promoting dendrite structure re-finement.Meanwhile,solute Ce improved the eutectic precipitation conditions of σ phase and further promoted its nucleation,while the dendrite refinement limited its growth space.Finally,more fine and dispersed σ phase particles formed in S32654 with Ce addition.The refinement of dendrite structure and σ phase will reduce the temperature and time required for high-temperature homogenization,which is beneficial to the hot working of this steel.

School of Metallurgy,Northeastern University,Shenyang 110819,China;School of Materials and Metallurgy,University of Science and Technology Liaoning,Anshan 114051,China

[1]Shucai Zhang;Jiangtao Yu;Huabing Li;Zhouhua Jiang;Yifeng Geng;Hao Feng;Binbin Zhang;Hongchun Zhu-.Refinement mechanism of cerium addition on solidification structure and sigma phase of super austenitic stainless steel S32654)[J].材料科学技术（英文版）,2022(07):105-114

S32654

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