摘要
以一种镍基单晶高温合金为基础,设计了0Ta和3.5Ta两种合金。采用光学显微镜和扫描电镜等手段研究了Ta元素对铸态和热处理态组织的影响,并基于组织确定了合适的热处理制度。最后分析了Ta对中温持久性能的影响。结果表明:相较于0Ta合金,3.5Ta铸态合金的一次枝晶间距提高约36.5μm,γ/γ′共晶含量增大约3倍,且固溶热处理窗口明显更窄。两合金在1280℃分别缓慢升至1325℃和1330℃并保温4 h后,枝晶偏析均不明显,共晶完全消除,且均未发生初熔,但3.5Ta合金在1330℃固溶后微孔较多。最终的热处理制度确定为:1280℃→1325℃/4h(0.1℃/min),空冷→1150℃/4h,空冷→870℃/24h,空冷。热处理后3.5Ta合金在760℃/810 MPa下的持久寿命约为0Ta合金的2倍,而断后伸长率低于0Ta合金。
Based on a Ni-based single crystal superalloy,two kinds of 0Ta and 3.5Ta alloys were designed.By using optical microscopy(OM)and scanning electron microscopy(SEM),the effects of Ta element on the as-cast and heat-treated microstructures were investigated,and appropriate heat treatment regime was confirmed according to the microstructures.Finally,the effects of Ta on the stress rupture properties were analyzed.The results indicate that,compared with the 0Ta alloy,the primary dendrite spacing grows by 36.5μm,theγ/γ′eutectic content is increased by 3 times,and the solution heat treatment window is narrowed greatly for the as-cast 3.5Ta alloy.After raising temperature slowly from 1280℃to 1325℃and 1330℃,respectively,and holding for 4 h for the two alloys,the dendritic segregations are not obvious,the eutectics are completely eliminated,and no incipient melting occurs.However,there are more micropores formed during solution treatment at 1330℃for the 3.5Ta alloy.The final heat treatment process is determined as follows℃1280℃■1325℃/4 h,air cooling(AC)→1150℃/4 h,AC→870℃/24 h,AC.After heat treatment,the stress rupture life of 3.5Ta alloy tested under 760℃/810 MPa is about 2 times of that of 0Ta alloy,but the elongation after fracture is lower than that of 0Ta alloy.
作者
李亚微
葛志成
谢光
黄亚奇
卢玉章
LI Ya-wei;GE Zhi-cheng;XIE Guang;HUANG Ya-qi;LU Yu-zhang(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,Liaoning,China;Institute of Corrosion Science and Technology,Guangzhou 510070,Guangdong,China)
出处
《铸造》
2025年第7期939-949,共11页
Foundry
基金
航空发动机及燃气轮机基础科学中心项目(P2022-C-IV-001-001)
国家自然科学基金项目(52271042、U2141206和U2241283)
中国科学院依托重大科技基础设施的建制化科研项目(JZHKYPT-2021-01)。
关键词
单晶高温合金
TA
热处理
显微组织
持久性能
single crystal superalloy
Ta
heat treatment
microstructure
stress rupture property
