Papers by Author: Yong Su

Abstract: By means of calculating stacking fault energy (SFE), measuring creep properties and contrast analysis of dislocation configuration, an investigation has been made into the influence of the stacking fault energy on the creep mechanism of the single crystal nickel-based superalloy. Results show that the alloy at 760¡æ has a lower stacking fault energy (SFE), and the SFE of the alloy increases with the temperatures. The deformed mechanism of the alloy during creep at 760¡æ is the cubical γ′ phase sheared by <110> super-dislocation which may be decomposed to form the configuration of (1/3)<112> super-Shockley partials dislocation plus the superlattice intrinsic stacking fault (SISF). The deformed mechanism of the alloy which possesses the higher SFE at 1070¡æ is the screw or edge super-dislocation shearing into the rafted γ′ phase. The SFE of the alloy at 980¡æ is intervenient between the ones of 760¡æ and 1070¡æ, the deformation mechanism of the alloy during creep is the rafted γ′ phase sheared by <110> screw and edge super-dislocations which may be decomposed into the configuration of (1/2)<110> partial dislocation plus APB.

Abstract: By means of the finite element method (FEM) for calculating the von Mises stress and strain energy density in the cubic γ/γ′ phases, the regularity of γ′ phase directional growth is investigated. Results show that the change of the strain energy density in the different planes of the cubical γ′ phase occurs during tensile creep of alloy, the cubical γ′ phase is directionally grown, along the crystal plane with bigger strain energy, to transform into the mesh-like rafted structure along the direction perpendicular to the applied stress axis. The change of the atomic potential energy, interfacial energy and lattice misfit stress is thought to be the driving force for promoting the elements diffusion and directional growth of γ′ phase.