Influence of element Re on deformation mechanism within γ' phase of single crystal nickel-based superalloys during creep at elevated temperatures

摘要

By means of creep properties measurement and microstructure observation, combined with the contrast analysis of dislocation configurations, an investigation has been made into the effects of the element Re on the deformation mechanisms within the γ' phase of single crystal nickel-based superalloys during creep at elevated temperatures. Results show that, compared to free-Re superalloy, 2% Re alloy at 980 ℃ displays a lower strain rate and better creep resistance. In the later stage of creep at 980 ℃, the deformation feature of the free-Re superalloy is the <110> super-dislocation shearing into the rafted γ' phase and slipping on {111} planes, and the Kear-Wilsdorf (KW) locks are formed within the γ' phase of 2% Re single crystal nickel-based superalloy. And the dislocations in KW locks in Re-containing superalloy under thermal activation may be re-activated for slipping on {111} planes to release the KW locks as the creep temperature further increases to 1070 ℃.