Ta对IN617B镍基高温合金凝固组织及元素偏析的影响

• 作 者: 高双 宋振峰 何博 周兰章 侯介山
• 机 构: 上海工程技术大学 材料工程学院,上海 201620;上海工程技术大学 高温合金精密成型研究中心,上海 201620;中国科学院 金属研究所,沈阳 110016
• 出 处: 中国有色金属学报（英文版）
• 发表日期: 2022年2期
• 关键词: IN617B nickel-base superalloy Ta addition solidification microstructure element

IN617B镍基高温合金是700℃先进超超临界燃煤电站的主要候选材料.采用OM、SEM、TEM、EDS、EPMA和热力学计算等方法研究Ta对IN617B镍基高温合金凝固行为及组织的影响.研究结果表明:IN617B合金的凝固组织呈典型的树枝晶形貌,在枝晶间和晶界处分布着网状的M6C、板条状的M23C6和颗粒状的Ti(C,N);Ta的加入促进富Ta的MC碳化物的析出,显著抑制M6C和M23C6的析出,并且降低合金元素Al、Mo和Ti的偏析程度;Ta的加入明显降低MC碳化物的析出温度,但未改变合金的凝固路径:L→ γ→MC或Ti(C,N)→M6C→M23C6,在凝固过程中MC和Ti(C,N)易与M6C碳化物形成共生组织.该研究为IN617B镍基高温合金的合金优化和铸造组织调控提供理论基础和数据支持.“,”IN617B nickel-base superalloy is considered as a good candidate material in 700 ℃ advanced ultra- supercritical 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→ γ 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.