Molecular dynamics simulation of the structural evolution of misfit dislocation networks at γ/γ′ phase interfaces in Ni-based superalloys

Abstract

The structural evolution of misfit dislocation networks at γ/γ′ phase interfaces in Ni-based single crystal superalloys under tensile loading and temperatures is simulated by molecular dynamics. From the simulation, we find that, with increasing load or temperature, the patterns of dislocation networks on the (100), (110) and (111) phase interfaces change from regular to irregular or disappear. Under the same load and temperature, the dislocation networks of the different phase interfaces show different degrees and patterns of damage. The density and stability of the dislocation networks decrease with increasing temperature. When the interfacial dislocation networks become more regular, the γ/γ′ interfaces become more stable. The simulated results are supported by related experimental findings. Moreover, based on MD simulations, the averaged stress–strain responses for different phase interfaces under loading are presented. The results indicate that the combined influences of temperature and load play an important role for the structure evolution of misfit dislocation networks at γ/γ′ phase interfaces of Ni-based superalloys.

Keywords:

• molecular dynamics simulation
• interface
• dislocation network
• Ni-based superalloys

Acknowledgements

This research was supported by National Natural Science Foundation of China (Grant No. 11072026 and No. 10632020), the Fundamental Research Funds for the Central Universities, and BJTU Excellent Doctor's Science and Technology Innovation Foundation (No. 141039522). W.P. Wu thanks the China Scholarship Council (CSC) for financial assistance.