A crack growth model for nickel-based powder metallurgy superalloy considering creep zone at crack tip

In this paper, the creep crack growth behavior of powder alloy materials for turbine disks was studied. The experimental results show that the creep crack growth rate at 700 & DEG;C is significantly higher than that at 600 & DEG;C, and the main form of the crack growth is intergranular fracture. It is found that there is an obvious dispersion state in the early stage of creep crack growth, which cannot be described by creep fracture parameters based on the linear elastic assumption, such as C(t),Ct. To solve this problem, a rate model considering creep zone at crack tip was proposed, which can describe the crack growth rate curve uniformly. The prediction deviation of creep crack growth time is approximately 1.5X.