Creep behavior in a γ′ strengthened Co-Al-W-Ta-Ti single-crystal alloy at 1000 °C

 The tensile creep behavior and microstructural stability of a Co-Al-W-Ta-Ti single-crystal alloy were investigated at 1000 °C. Long-term aging at 1000 °C for 1000 h revealed stable γ-γ′ structure with 75% γ′ volume fraction. The measured positive lattice misfit resulted in directional coarsening parallel to the applied stress during creep. The γ-γ′ interfacial dislocation networks and shearing of γ′ precipitates with stacking faults and antiphase boundaries appeared to contribute to the creep resistance with 1.0% creep stain.