Abstract
A methodology for determining the preferred site occupancy of various alloying elements within ordered γ′ precipitates was developed and applied to Rene88 samples. The method utilized atom probe tomography and X-ray diffraction techniques with controlled monochromated synchrotron beams to determine element positions. Samples were solutionized at 1423 K (1150 C) for 30 minutes and cooled at 24 K/min with subsequent aging at 1033 K (760 C). The synchrotron X-ray diffraction results indicate that niobium prefers to reside on the aluminum sublattice site of the γ′ phase. Additionally, the results indicate that chromium prefers the nickel sublattice sites, while cobalt is likely to occupy both the aluminum and nickel sublattice sites. The X-ray results on the chromium occupancy disagree with atom probe results from the same alloy that indicate that chromium prefers the aluminum sublattice sites.
| Original language | English |
|---|---|
| Pages (from-to) | 31-38 |
| Number of pages | 8 |
| Journal | Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science |
| Volume | 44 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2013 |
| Externally published | Yes |
Funding
For this research, the commercial material Rene88 was used because it is a successful commercially relevant alloy with a low g/g¢ misfit. The alloy has the following composition (at. pct): 18.02Cr-13.00Co-4.74Ti-4.45Al-2.48Mo-1.21W-0.46Nb, remaining Ni. Samples were cut from a disk produced and tested under work supported by the Defense Advanced Research Projects Agency,[32] and solutionized at 1423 K (1150 °C) for 30 minutes, followed by cooling at 24 K/minutes, and then aged at 1033 K (760 °C) for 200 hours and air cooled. Use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The authors greatly appreciate technical help from M. Lucas and E. Karapetrova in conducting the synchrotron X-ray experiments. Work at the Air Force Research Laboratory was supported by on-site contract No. FA8650-10-D-5226 conducted through UES, Inc., Dayton, Ohio, and by the Institute for Science and Engineering Simulation (ISES) under contract No. FA8650-08-C-5226.
| Funders | Funder number |
|---|---|
| Institute for Science and Engineering Simulation | FA8650-08-C-5226 |
| U.S. Department of Energy | |
| Defense Advanced Research Projects Agency | |
| Office of Science | |
| Basic Energy Sciences | DE-AC02-06CH11357, FA8650-10-D-5226 |