Microstructure and creep behavior of a single crystal nickel-based superalloy
By means of the measurement of creep curves and microstructure observation,an investigation has been made into the microstructure and creep behaviors of a single crystal nickel-based superalloy.Results show that,in the range of the applied temperatures and stresses,the superalloy displays an obvious sensibility of the applied temperatures and stresses.In the action of the applied temperature and stresses,the directional diffusion of the elements occurs,which promotes the cubic γ phase transformed into the N-type rafted structure along the direction vertical to the applied stress axis.In the later stage of creep,the deformed mechanism of the alloy is <110> super-dislocation shearing into the rafted γ phase,and the distortion of the rafted γ.phase occurs in the constricted region near the fracture.The dislocation climbing over the γ.raft phase is thought to be the deformed mechanism of the alloy during the steady state creep.The size of the rafted γ.phase formed at 1072℃ is smaller than the one formed at 1040℃,which results in the dislocations climbing easily over the rafted γ.phase.Therefore,the alloy displays a higher strain rate during high temperature creep.According to the theory of dislocation piled up,an expression has been deduced to describe the phenomenon of the dislocation climbing over the rafted γphase.
Single crystal nickel-base superalloy Microstructure Creep behavior Dislocation climbing
Sugui Tian Lili Yu Huichen Yu Benjian Qian Jun Xie
School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110178,China Beijing Institute of Aeronautical Materials,Beijing 100095,China
国际会议
成都
英文
233-238
2009-10-16（万方平台首次上网日期，不代表论文的发表时间）