Dislocation network with pair-coupling structure in {111} γ/γ′ interface of Ni-based single crystal superalloy

作者：Ru, Yi; Li, Shusuo; Zhou, Jian; Pei, Yanling; Wang, Hui^*; Gong, Shengkai^*; Xu, Huibin

来源：Scientific Reports, 2016, 6(1): 29941.

DOI：10.1038/srep29941

• STRESS CREEP ANISOTROPY
• HIGH-TEMPERATURE CREEP
• DYNAMICS SIMULATION
• LATTICE MISFIT
• MICROSTRUCTURE
• MECHANISMS
• RHENIUM
• ALLOYS
• MOTION

The gamma/gamma' interface dislocation network is reported to improve the high temperature creep resistance of single crystal superalloys and is usually found to deposit in {001} interface. In this work, a new type of dislocation network was found in {111}gamma/gamma' interface at a single crystal model superalloy crept at 1100 degrees C/100 MPa. The dislocations in the network are screw with Burgers vectors of 1/2 a < 110 > and most interestingly, they exhibit a pair-coupling structure. Further investigation indicates that the formation of {111} interface dislocation network occurs when the gamma' raft structure begins to degrade by the dislocations cutting into the rafted gamma' through the interface. In this condition, the pair-coupling structure is established by the dislocations gliding in a single {111} plane of gamma', in order to remove the anti-phase boundary in gamma'; these dislocations also act as diffusion channels for dissolving of the gamma' particle that is unstable under the interfacial stress from lattice misfit, which leads to the formation of {111}-type zigzag interface. The formation of this network arises as a consequence of more negative misfit, low-alloying gamma' particle and proper test conditions of temperature and stress.

• 出版日期2016-8-11
• 单位北京航空航天大学