γ/γ′ interface strengthening of Re in single crystal superalloys
(1.北京市北京航空材料研究所先进高温结构材料国防科技重点实验室
2.National Key Laboratory of Advanced High Temperature Structural Materials,Beijing Institute of Aeronautical Materials, Beijing 100095, China)
2.National Key Laboratory of Advanced High Temperature Structural Materials,Beijing Institute of Aeronautical Materials, Beijing 100095, China)
Abstract: Based on analysis of three alloys with various Re contents, the effects of Re on the interfacial structure characteristic and interfacial dislocations of γ/γ′ in single crystal superalloys were investigated. A high resolution transition electron microscopy (HRTEM) technique was used to detect the structure characteristic of γ/γ′ interface. The interfacial dislocations of γ/γ′ were analyzed with TEM. The results show that as Re content increases, the interfaces of γ/γ′ become orderly, the atomic arrangements at interfaces are more uniform, the number of mismatch dislocations increases and transition areas between γ and γ′ phases become narrow. That Re changes the interfacial structure promotes the formation of dense, regular and homogeneous interfacial dislocation networks in short time during creep at 1 100 ℃ and 140 MPa, which results in strengthened γ/γ′ interface at elevated temperature.
Key words: single crystal superalloy; γ/γ′; interface strengthening; dislocation; Re