Creep Behavior of a Single Crystal Nickel-Based Superalloy Containing Re/Ru at 1100°C/137MPa

Creep behavior of a heat treated single crystal nickel base superalloy containing Re/Ru under the test condition of 1100°C/137MPa high temperatures was investigated. The experimental results showed that the segregation extent of elements in the dendrite and inter-dendrite regions of single crystal superalloy decreases by heat treatment at high temperature. The creep life of the alloy at 1100°C/137MPa was measured to be 321 h displaying a better creep resistance. Wherein, significant amount of fine cubiodal γ′ particles precipitated in the γ matrix channels are considered to be the main reason of the alloy having the better creep resistance. The deformation feature of the alloy during steady state creep is dislocations slipping in the γ matrix and climbing over the rafted γ′ phase. But in the latter stage of creep, the deformation feature of the alloy is dislocations shearing into the rafted γ′ phase. As creep goes on, the main / secondary slipping dislocations in the alloy are alternately activated to result in the initiation and propagation of the cracks along the interface of the rafted γ′/γ phase up to fracture, which is thought to be the fracture mechanism of the alloy during creep.