ISSN: 1003-6326
CN: 43-1239/TG

Vol. 29    No. 3    March 2019

Orientation dependence of transverse tensile properties of nickel-based third generation single crystal superalloy DD9 from 760 to 1100 °C
Wan-peng YANG, Jia-rong LI, Shi-zhong LIU, Zhen-xue SHI, Jin-qian ZHAO, Xiao-guang WANG
(Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China)
Abstract: At temperatures ranging from 760 to 1100 °C, the tensile properties of a nickel-based third generation single crystal superalloy DD9 with [100], [120] and [110] orientations were studied. The microstructures and fracture surfaces were observed by OM, SEM and TEM. Results show that the tensile strength of [100] specimen is higher than that of [120] and [110] specimens at 760 and 850 °C; while at the temperatures higher than 980 °C, the tensile strength of all specimens has little difference. The fracture mechanisms of [100], [120] and [110] specimens are the same at 760 and 980 °C. At 1100 °C, the fracture surfaces of [100] and [120] specimens are characterized by dimple features; while [110] specimen shows mixed quasi-cleavage and dimple featured fracture surfaces. At 760 °C, obvious superlattice stacking faults (SSFs) are observed only in [100] specimen; while at 1100 °C, the dislocation configurations of all specimens are similar. The difference in the number of potential active slip systems in [100], [120] and [110] specimens during the tensile deformation process is the main reason for the transverse tensile anisotropy.
Key words: third generation single crystal superalloy; DD9; transverse tensile properties; anisotropy; fracture surface
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
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