Effect of heat treatment on rotating bending fatigue properties of K417G nickel-base superalloy

A review on isothermal rotating bending fatigue failure: Microstructural and lifetime modeling of wrought and additive manufactured alloys

“…It was found (Figure 14B) that the cracks in the alloy were most prevalent at the eutectic boundary and the trifurcate grain boundaries of the wrought alloy. In addition, it was discovered by Yu et al 71 that there was a significant quantity of carbide chains in the area surrounding the fractures in wrought materials, and we expect the same phenomenon in AM'd materials. This finding suggested that the continuous distribution of carbides along the grain boundaries played a role in the beginning and spread of the cracks.…”

“…(A) Fracture surface of AM'd Inconel 718 in RBF test, 62 (B) carbide chains and microcracks of K417G alloy in RBF test of wrought material 71 . [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…68,69 The fatigue limit in AM'd Inconel 718 was published by Radhakrishnan et al 62 in the RBF test, and Nezhadfar et al 70 reported results that were comparable to those in the conventional fatigue test. During the aging treatment of the Ni-based superalloy at temperatures between 850 C and 950 C in wrought material, Yu et al 71 found that the segregation of carbon, chromium, and molybdenum at the grain boundaries promoted the development of M 23 C 6 carbides. The element has a poor diffusion rate when the alloy is aged at 850 C, and the carbide particles tend to congregate and form chains during this process.…”

“…The blue Chromia can be formed in about 1:3 Â 10 6 cycles. Similar to how the red, purple, and yellow oxides form in 9.8, 6.6, 3.4 Â 10 5 cycles, the blue chromia canF I G U R E 1 4 (A) Fracture surface of AM'd Inconel 718 in RBF test,62 (B) carbide chains and microcracks of K417G alloy in RBF test of wrought material 71. [Colour figure can be viewed at wileyonlinelibrary.com]…”

Microstructure and Stress Rupture Properties of K417G Superalloy at Different Hot Isostatic Pressing Temperatures

“…K417G, a nickel-based precipitation-hardened cast superalloy, has excellent high-temperature mechanical properties and hot-corrosion resistance after being modifed on the basis of K417 superalloy and is used for turbine blades and guide blade components of aircraft engines. [5,6] With the continuous development of advanced blades, micrometallurgical defects, such as pores, shrinkage, and slag patches, inevitably appear in the casting process [7]. Although the casting process has been constantly improved and micrometallurgical defects in superalloy castings have been reduced to a certain extent, it cannot completely eliminate the micrometallurgical defects such as shrinkage and the volume fraction of shrinkage content that can generally reach more than 0.3% [8,9].…”