| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Hume-Rothery Symposium: Thermodynamics, Phase Equilibria and Kinetics for Materials Design and Engineering
|
| Presentation Title |
Thermodynamic Modeling of Precipitates of Topologically Close-packed Phases |
| Author(s) |
Thomas Hammerschmidt |
| On-Site Speaker (Planned) |
Thomas Hammerschmidt |
| Abstract Scope |
The precipitation of topologically close-packed (TCP) phases in superalloys is highly undesirable due to the detrimental effect on the mechanical properties. The structural stability of bulk TCP phases in thermodynamic equilibrium is well understood but little is known about the dominating factors that govern the formation of TCP phase precipitates within a superalloy matrix. Here, a thermodynamic modelling approach of the TCP phase precipitates is presented. It connects the experimentally observed local chemical composition with empirical maps of bulk TCP phase stability and with solidification modelling based on CALPHAD databases. Several examples for Ni-base and Co-base superalloys indicate that the precipitates exhibit chemical compositions that are expected to form a TCP phase also as bulk material. An example of the limits of this purely thermodynamic interpretation is the stress-induced formation of TCP phases that was observed recently in low-cycle fatigue tests of a Ni-based superalloy. |
| Proceedings Inclusion? |
Undecided |