STUDY ON THE THREESTAGE CREEP OF THE DD3SINGLE CRYSTAL SUPERALLOY
STUDY ON THE THREE-STAGE CREEP OF THE DD_3 SINGLE CRYSTAL SUPERALLOY

Materials and Testing, Shanghai Jiao Tong University, Shanghai 200030, China The threestage creep behavior of DD3 single crystal superalloy had been studied. The results show that the creeprupture properties of DD3 single crystal satisfy the requirements for high performance turbine blade application. The influence of crystal orientation on the creeprupture property of DD3 single crystal was tested and discussed. An engineering criterion to evaluate the regimes of secondary and tertiary creep is proposed, and this method gives a reasonable result for practical applications. The fractography and TEM micrography of the tested specimens had been studied, and it is determined that the glidecontrolled creep is the basic creep mechanism of DD3 single crystal at intermediate temperature, but the thermally activated processes become dominant at higher temperature.