Abstract
M2B-type borides in nickel-based superalloys containing boron subjected to long-term aging treatments were investigated by means of analytical transmission electron microscopy. Contrast analysis and electron diffraction show that the boride precipitations have dual-phase structures (I4/mcm, C16; Fddd, Cb) with a high density of stacking faults. The faulted planes and displacement vectors are determined as (1 1 0)C16 and [ 11̄1]C16/4 in C16 structure and (1 0 0)Cb and [0 1 1]Cb/4 in Cb structure. Structural models based on a polyhedron of square anti-prisms are proposed not only to rationalize the stacking faults, 60 rotation twin and the intergrowth of structural variants, but also to interpret the newly observed structure in M2B-type borides.
Original language | English (US) |
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Pages (from-to) | 70-81 |
Number of pages | 12 |
Journal | Acta Materialia |
Volume | 68 |
DOIs | |
State | Published - Apr 15 2014 |
Funding
This work is supported by the National Basic Research Program of China ( 2009CB623705 and 2010CB631206 ). The authors are grateful to J. Wang for bulk sample preparation and to Prof. S.B. Mi for useful discussions.
Keywords
- Intergrowth
- MB-type boride
- Nickel-based superalloy
- Polytypic structure
- Transmission electron microscopy
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys