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 degrees of the [001] direction are observed at 760 degrees 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 degrees C and 785 MPa is a < 112 > dislocation ribbon passing through both gamma and gamma' 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. (c) 2012 Published by Elsevier B.V.