Creep Behaviors of a Single Crystal Nickel-Based Superalloy Containing 4.2Re

摘要

By the measurement of creep curves and microstructure observation, an investigation has been made into the creep behaviors and microstructure evolution of a single crystal nickel-based superalloy containing 4.2%Re. Results show that the superalloy displays an obvious sensibility on the applied temperatures and stresses in the range of the applied temperatures and stresses. During the initial creep, the cubical γ' phase in the alloy is transformed into an N-type rafted structure along the direction vertical to the applied stress axis. After crept up to fracture, the rafted γ' phase in the region near fracture is transformed into a twisted configuration. The dislocation climbing over the rafted γ' phase is considered to be the main deformation mechanism of the alloy during the steady creep state, and dislocations shear into the rafted γ' phase is the main deformation mechanism of the alloy in the later stage of creep.