Microstructural Study of Cold-Sprayed CoCrFeNiMn High Entropy Alloy

Akisin, Cletus J.; Dovgyy, Bogdan; Bennett, Christopher J.; Pham, Minh Son; Venturi, Federico; Hussain, Tanvir

Abstract

The rapid development of cold spraying technology for additive manufacturing of engineering components has made it a viable option for developing thick deposits from high-entropy alloys (HEAs). The microstructure of cold-sprayed CoCrFeNiMn deposit was investigated in this study using electron backscattered diffraction, scanning electron microscopy, and finite element analysis (FEA). The limited studies on the impact deformation behavior of the HEA during cold spraying, limiting our understanding of impact phenomena, and interactions between the HEA particles under ultra-high strain rate deformation motivated this study. From the microstructural characterization, heterogeneous microstructure appears to be formed in the cold-sprayed HEA deposit, comprising of equiaxed ultrafine grains at the particle–particle interfacial regions and coarse grains at the particle interiors. The FEA reveals large strain (> 250%) and temperature (> 90% of the alloy solidus temperature), mainly at the splat’s interfaces. Adiabatic shear instability and rotational dynamic recrystallization resulting from heat accumulation and high strain are believed to be responsible for these observations during the ultra-high strain rate deformation of the HEA. The large deformation and grain refinement experienced by the HEA resulted in greater deposit hardness when compared with the sprayed powder, with the nanohardness increasing from 1.16 GPa in the powder to 5.14 GPa in the deposit. This study explores and provides an understanding of the deformation behavior of the HEA and the resulting microstructure during cold spraying.

Citation

Akisin, C. J., Dovgyy, B., Bennett, C. J., Pham, M. S., Venturi, F., & Hussain, T. (2023). Microstructural Study of Cold-Sprayed CoCrFeNiMn High Entropy Alloy. Journal of Thermal Spray Technology, 32, 2539–2562. https://doi.org/10.1007/s11666-023-01646-7

• Journal Article Type: Article
• Acceptance Date: Aug 7, 2023
• Online Publication Date: Aug 22, 2023
• Publication Date: 2023-12
• Deposit Date: Feb 5, 2024
• Publicly Available Date: Feb 6, 2024
• Journal: Journal of Thermal Spray Technology
• Print ISSN: 1059-9630
• Electronic ISSN: 1544-1016
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 32
• Pages: 2539–2562
• DOI: https://doi.org/10.1007/s11666-023-01646-7
• Keywords: adiabatic shear instability, cold spray additive manufacturing, dynamic recrystallization, finite element analysis, high-entropy alloys
• Public URL: https://nottingham-repository.worktribe.com/output/24869877
• Publisher URL: https://link.springer.com/article/10.1007/s11666-023-01646-7