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Hardness Evolution of Solution-Annealed LPBFed Inconel 625 Alloy under Prolonged Thermal Exposure

Authors :
Fabrizio Marinucci
Giulio Marchese
Emilio Bassini
Alberta Aversa
Paolo Fino
Daniele Ugues
Sara Biamino
Source :
Metals, Vol 12, Iss 11, p 1916 (2022)
Publication Year :
2022
Publisher :
MDPI AG, 2022.

Abstract

Thanks to its high weldability, Inconel 625 (IN625) can be easily processed by laser powder bed fusion (LPBF). After production, this alloy is typically subjected to specific heat treatments to design specific microstructure features and mechanical performance suitable for various industrial applications, including aeronautical, aerospace, petrochemical, and nuclear fields. When employed in structural applications, IN625 can be used up to around 650 °C. This limitation is mainly caused by the transformation of metastable γ″ phases into stable δ phases occurring under prolonged thermal exposure, which results in drastically reduced ductility and toughness of the alloy. Because the microstructure and mechanical properties change during thermal exposure, it is essential to study the material simulating possible service temperatures. In the current study, LPBFed IN625 samples were solution-annealed and then subjected to thermal exposure at 650 °C for different times up to 2000 h. The characterization focused on the evolution of the main phases, γ″ and δ phases, and their influence on the hardness evolution. The microstructure and hardness of the heat-treated LPBFed IN625 samples were compared with data related to the traditionally processed IN625 alloy (e.g., wrought state) reported in the literature.

Details

Language :
English
ISSN :
20754701
Volume :
12
Issue :
11
Database :
Directory of Open Access Journals
Journal :
Metals
Publication Type :
Academic Journal
Accession number :
edsdoj.2321d20bd8244901bd4b35145a492013
Document Type :
article
Full Text :
https://doi.org/10.3390/met12111916