Creep behavior of a novel Co-Al-W-base single crystal alloy containing Ta and Ti at 982 ^∘C

¹ State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
² National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China

^a Corresponding author: qfeng@skl.ustb.edu.cn

Abstract

The tensile creep behavior of a Co-Al-W-base single crystal alloy containing Ta and Ti was investigated at 982 ^∘C and 248 MPa. The lattice misfit of experimental alloy was measured to be positive by synchrotron X-ray diffraction at high temperature, and long term heat treatment at 1000 ^∘C for 1000 h revealed a γ^′ volume fraction of 75% without secondary phases. The creep test indicated that the creep properties of experimental alloy exceeded commercial 1st generation Ni-base single crystal superalloy CMSX-3 with respect to the rupture life. The initial cuboidal γ^′ precipitates directionally coarsened parallel to the applied stress axis during the creep process. The stacking faults in {111} planes within γ^′ rafts were the primary creep deformation mode by TEM investigation.