Orientation dependence of creep properties and deformation mechanism in DD6 single crystal superalloy at 760 °C and 785 MPa

The effect of orientation on the creep properties of DD6 single crystal superalloy is investigated. The results show that anisotropic creep behaviors of DD6 alloy within 20° of the [001] direction are observed at 760 °C and 785 MPa. The [001] direction and the [001]-[011] boundary exhibit lower primary creep strain and longer creep rupture lives than the [001]-[111] boundary. In addition, the major creep deformation mechanism of DD6 single crystal superalloy at 760 °C and 785 MPa is a〈112〉 dislocation ribbon passing through both γ and γ′ phases. The interaction between 〈112〉{111} systems is the principle hardening mechanism for the transition from primary creep to secondary creep, the interaction leads to the anisotropy of primary creep and creep rupture lives for the [001] direction, the [001]-[011] boundary and the [001]-[011] boundary.