| About this Abstract |
| Meeting |
2019 TMS Annual Meeting & Exhibition
|
| Symposium
|
Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys III
|
| Presentation Title |
Elucidating the Effects of Cr on the Microstructure, Oxidation Resistance and Mechanical Properties of Cobalt-based Superalloys |
| Author(s) |
Ding-Wen Chung, Jacques Perrin Toinin, Daniel Ng, Eric Lass, David Seidman, David Dunand |
| On-Site Speaker (Planned) |
Ding-Wen Chung |
| Abstract Scope |
Chromium is known to be an essential element for providing oxidation resistance to Co-based superalloys, yet the archival literature frequently reports contradictory effects on its physical and mechanical properties. To understand the fundamental contributions of Cr, we varied systematically its concentration to investigate its effects on the thermodynamic, microstructural and mechanical properties of several Co-based superalloys. Chromium is shown to de-stabilize the gamma-prime (L12)-phase and to change its morphology. Correlative atom-probe tomography and synchrotron x-ray diffraction demonstrate that Cr significantly reduces the gamma(f.c.c)/gamma-prime lattice parameter misfit by supplanting W from the gamma-prime phase. Isothermal oxidation experiment performed at 900˚C demonstrate that 4 at. % Cr is sufficient to decrease the oxidation kinetics by two orders of magnitude. Preliminary results show, that contrary to the archival literature, Cr does not impact the mechanical creep properties as significantly. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |