A phenomenological creep model for nickel-base single crystal superalloys at intermediate temperatures

Siwen Gao, Ruhr-Universität Bochum, Germany

For the purpose of good reproduction and prediction of creep deformation of \ nickel-base single crystal superalloys at intermediate temperatures, a phenomenological creep model is developed, which accounts for the typical γ/γ′ microstructure and the individual thermally activated elementary deformation processes in different phases. The internal stresses from γ/γ′ lattice mismatch and deformation heterogeneity are introduced through an efficient method. The strain hardening, the Orowan stress, the softening effect due to dislocation climb along γ/γ′ interfaces and the formation of ⟨112⟩ dislocation ribbons, and the Kear–Wilsdorf-lock effect as key factors in the main flow rules are formulated properly. By taking the cube slip in ⟨110⟩{100} slip systems and ⟨112⟩{111} twinning mechanisms into account, the creep behavior for [110] and [111] loading directions are well captured.

« back

Session T1: Tuesday, 26 June 2018

Start: 12:15 p.m.
End: 12:30 p.m.