Investigation on the Microstructure and Segregation of Superalloy FGH96 by Direct Laser Forming

Abstract:

Direct laser forming directional solidification experiments were performed by using nickel-base superalloy as substrate and powder FGH96 as cladding material. The solidification microstructure of the cladding layer was investigated. Results showed that as-deposited microstructure was directionally solidified dendrites with the primary dendrite arm spacing of approximately 3μm and the secondary arm was small or even degenerated. According to the theory of columnar/equiaxed transition (CET) in front of the solid/liquid interface, it was found that in the single-path multi-layer cladding layers and multi-path multi-layer cladding layers, the microstructure with the same crystallographic orientation as the substrate was obtained by reasonably selecting the processing parameters. Composition segregation analysis showed a very uniform distribution of elements,and the segregation ratios were close to 1.

• Periodical: Applied Mechanics and Materials (Volume 464)
• Pages: 58-63
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.464.58
• Online since: November 2013
• Authors: Hai Yang Zhang, An Feng Zhang*, Bin He, Xing Kun Shi
• Keywords: Composition Segregation, Direct Laser Forming, Directional Solidification, Microstructure, Superalloy FGH96

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