Atomic imaging of the interface between M₂₃C₆-type carbide and matrix in a long-term ageing polycrystalline Ni-based superalloy

Abstract

Besides the well-known cube-on-cube orientation relationship (OR) between M₂₃C₆ carbide and matrix, we have determined a new OR named as the twin-related OR in a long-term ageing Ni-based superalloy on the basis of the extensive and detailed electron diffraction analyses. Furthermore, by means of atomic-resolution high angle annular dark-field imaging technique which is implemented in the aberration-corrected scanning transmission electron microscope, we elucidated the interfacial characteristics between M₂₃C₆ and matrix for above two types of ORs. Taking into account of the interfacial characteristics, we propose that the twin-related OR possesses a higher total interfacial energy. Thus, its frequency of occurrence is lower than that of the cube-on-cube OR though both ORs are usually seen in the long-term ageing samples.

Keywords:

• Nickel-based superalloys
• M₂₃C₆-type carbide
• crystallographic orientation relationship

Acknowledgements

The authors acknowledge the financial support from National Natural Foundation of China under 11327901 and National Basic Research Program of China under 2010CB631206 and 2009CB623705. And we are also grateful to J. Wang for bulk sample preparation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Natural Foundation of China [grant number 11327901]; National Basic Research Program of China [grant number 2010CB631206], [grant number 2009CB623705].