The Compositional Dependence of the Microstructure and Properties of CMSX-4 Superalloys

The Compositional Dependence of the Microstructure and Properties of CMSX-4 Superalloys

Yu, H. (TU Delft Novel Aerospace Materials)
Xu, W. (TU Delft Novel Aerospace Materials; Northeastern University China)
van der Zwaag, S. (TU Delft Novel Aerospace Materials)

2017-11-14

The degradation of creep resistance in Ni-based single-crystal superalloys is essentially ascribed to their microstructural evolution. Yet there is a lack of work that manages to predict (even qualitatively) the effect of alloying element concentrations on the rate of microstructural degradation. In this research, a computational model is presented to connect the rafting kinetics of Ni superalloys to their chemical composition by combining thermodynamics calculation and a modified microstructural model. To simulate the evolution of key microstructural parameters during creep, the isotropic coarsening rate and γ/γ′ misfit stress are defined as composition-related parameters, and the effect of service temperature, time, and applied stress are taken into consideration. Two commercial superalloys, for which the kinetics of the rafting process are selected as the reference alloys, and the corresponding microstructural parameters are simulated and compared with experimental observations reported in the literature. The results confirm that our physical model not requiring any fitting parameters manages to predict (semiquantitatively) the microstructural parameters for different service conditions, as well as the effects of alloying element concentrations. The model can contribute to the computational design of new Ni-based superalloys.

http://resolver.tudelft.nl/uuid:38ab244c-bf92-4174-8a0a-337fe916f2c4

https://doi.org/10.1007/s11661-017-4389-y

1073-5623

Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science, 1-11

Institutional Repository

journal article

© 2017 H. Yu, W. Xu, S. van der Zwaag