Effect of Ta addition on solidification microstructure and element segregation of IN617B nickel-base superalloy
Effect of Ta addition on solidification microstructure and element segregation of IN617B nickel-base superalloy
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DOI：
10.1016/s1003-6326(22)65815-11003
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发表时间：
2022-02-01
影响因子：
4.5
通讯作者：
Hou, Jie-shan
中科院分区：
文献类型：
--
作者：
Gao, Shuang;Song, Zhen-feng;Hou, Jie-shan
IN617B镍基高温合金被认为是700℃先进超超临界燃煤电厂的良好候选材料。通过OM、SEM、TEM、EDS、EPMA和热力学计算研究了Ta添加对IN617B合金凝固组织和元素偏析的影响。结果表明，凝固组织呈树枝状偏析，枝晶间分布有大量初生碳化物，如网状M6C、板条状M23C6和粒状Ti(C,N)。 Ta的添加促进了富TaMC的析出，显着抑制了M6C和M23C6的析出，降低了Al、Mo、Ti合金元素的偏析程度。 Ta的添加降低了MC碳化物的熔化温度，但不影响凝固路径，即L→γ基体→MC或Ti(C,N)→M6C→M23C6，其中MC和Ti(C,N)倾向于与M6C形成共生组织。本研究将为IN617B镍基高温合金的合金优化和铸造组织控制提供理论依据和数据支持。
IN617B nickel-base superalloy is considered as a good candidate material in 700 degrees C advanced ultrasupercritical coal-fired power plants. The effect of Ta addition on solidification microstructure and element segregation of IN617B alloy was investigated by OM, SEM, TEM, EDS, EPMA and thermodynamic calculation. The results showed that the solidification microstructure exhibited a dendritic segregation pattern with many primary carbides distributed in interdendritic regions, such as network M6C, lath M23C6 and granular Ti(C,N). The addition of Ta promoted the precipitation of Ta-rich MC significantly inhibiting the precipitation of M6C and M23C6, and reduced the segregation degree of Al, Mo and Ti alloying elements. The addition of Ta decreased the melting temperature of MC carbide, but did not impact the solidification path, that was, L -> gamma matrix -> MC or Ti(C,N) -> M6C -> M23C6, where MC and Ti(C,N) tended to form symbiotic microstructure with M6C. This study will provide theoretical basis and data support for the alloy optimization and casting structure control of IN617B nickel-based superalloy.