Abstract
The existence of inclusion in powder metallurgy nickel based superalloy limits fatigue life at high stress level. Therefore, considering the feature of inclusion-induced failure and choosing FGH96 as research object to carry out fatigue life tests, a fatigue life prediction method for inclusion-induced failure based on fracture mechanics was proposed. First, the application premise was clearly defined that this method was only suitable for inclusion-induced failure instead of slipband-induced failure. Then, for the physical small crack propagation stage, the crack propagation threshold and driving force correction were proposed to realize the unified equation description of small crack and long crack stage. Furthermore, a driving force characterization method for irregular shape defects including the effect of defect position and shape ratio was proposed. Finally, selecting the initial defect size, location, loading information and material properties as the input, the ±2.5 times error band life prediction was realized and the effect of environment, slipband-induced crack initiation and other situation were also analyzed. Meanwhile, S−N curves with different initial defect and position could be gained by this method, which to some extent explains the reason for fatigue life scatter.
| Translated title of the contribution | Understanding and mechanical method of failure induced by defects in powder metallurgy nickel-based superalloys |
|---|---|
| Original language | Chinese (Traditional) |
| Pages (from-to) | 40-54 |
| Number of pages | 15 |
| Journal | Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals |
| Volume | 33 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 2023 |