Investigation of the final stages of solidification and eutectic phase formation in Re and Ru containing nickel-base superalloys

• Published in: Journal of crystal growth 2010-07, Vol.312 (14), p.2137-2144
• Main Authors: Heckl, A., Rettig, R., Cenanovic, S., Göken, M., Singer, R.F.
• Format: Article
• Language: English
• Subjects: A1. 3-D microstructure; A1. Eutectic island; A1. FIB tomography; A1. Final stage solidification; A1. Microsegregation; B1. Nickel-base superalloys; Computer simulation; Condensed matter: structure, mechanical and thermal properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Diffusion in solids; Electron probes; Eutectics; Exact sciences and technology; Ion beams; Liquids; Materials science; Nickel base alloys; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Reconstruction; Solidification; Superalloys; Transport properties of condensed matter (nonelectronic)
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.03.041

The microstructure resulting from the final stages of solidification—commonly referred to as eutectic islands—has been analysed in detail for three nickel-base superalloys containing Re and Ru. Focused ion beam 3-D reconstruction and EBSD-analysis were used to clarify the origin of different eutectic structure types. One common type of parent 3-D eutectic structure was identified. The solidification process of the final solidifying liquid has been further investigated by electron probe microanalysis mappings along with DICTRA simulations. Two models for diffusion controlled phase transformations are shown to present a fair description of the solidification sequence.