(北京航空材料研究院,北京 100095)
摘 要: 用扫描电镜、能谱仪、X射线衍射技术和定量金相技术研究Ni-10Co-7.1W-1.7Mo-0.5Nb-6.9Ta-7.9Re-6.9Al- 0.008CNi3Al基高温合金的显微组织。实验表明:该合金由γ,γ′,γ + γ′共晶和Re3W相组成;Re是强负偏析元素,过量Re促使Re3W相的形成;合金中次生γ′、共晶γ′的固溶温度分别为1 330和1 360 ℃。采用1 290 ℃,2 h+ 1 330 ℃,6 h+1 360 ℃,6 h多级固溶处理实现γ′完全固溶并避免初溶,但该处理不能消除Re3W相,也不能实现Re的完全均匀化,适当降低Al,Ta和Re含量可以消除Re3W相。
关键字: Ni3Al基高温合金;铼;固溶处理;显微组织
(Beijing Institute of Aeronautical Materials, Beijing 100095, China)
Abstract:The microstructure of Ni3Al base superalloy with composition of Ni-10Co-7.1W-1.7Mo-0.5Nb-6.9Ta-7.9Re- 6.9Al-0.008C was investigated by SEM, EDS, XRD and quantitative metallographic method. The results show that the alloy consists of γ, γ′, eutectic (γ+γ′) and Re3W phases. Rhenium is a strong negative segregation element and the excessive amount of Re promotes the formation of Re3W phase. The solid solution temperatures of secondary γ′, eutectic γ′ are 1 330 ℃ and 1 360 ℃ respectively. By means of 1 290 ℃, 2 h+1 330 ℃, 6 h+1 360 ℃, 6 h multistep solid solution treatment, the full solid solution of γ′ phase is realized and the incipient melting is avoided. However, the Re3W phase can not be eliminated and the homogenization of Re is not completed by the above mentioned treatment. The proper solution is to modify the alloy composition so as to eliminate Re3W phase.
Key words: Ni3Al base superalloy; rhenium; solid solution treatment; microstructure