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Indentation Size Effect in CoCrFeMnNi HEA Prepared by Various Techniques
Jaroslav Čech1, Petr Haušild1, Miroslav Karlík1
1Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, 120 00 Prague, Czech Republic.
Materials (Basel, Switzerland)
|December 10, 2021
Summary
This study examined the Cantor alloy, a high entropy alloy (HEA), using indentation tests. The Nix-Gao model effectively describes hardness at larger depths, with modifications revealing submicrometer deformation mechanisms.
Area of Science:
- Materials Science
- Metallurgy
- Nanotechnology
Background:
- High entropy alloys (HEAs) are a significant class of materials with broad application potential, extensively studied over the past two decades.
- Model HEAs are crucial for understanding complex microstructures, properties, and deformation mechanisms due to the vast number of possible compositions.
- The Cantor alloy (Co, Cr, Fe, Mn, Ni) serves as a representative model HEA for such investigations.
Purpose of the Study:
- To investigate the microstructure and mechanical properties of the Cantor alloy prepared via different methods.
- To analyze the indentation size effect (ISE) on the hardness of the Cantor alloy.
- To evaluate the applicability of the Nix-Gao model and its modifications for describing the alloy's deformation behavior.
Main Methods:
- Preparation of the Cantor alloy using casting, melt-spinning, and spark plasma sintering techniques.
- Microstructural characterization of the prepared HEA samples.
- Nanoindentation measurements to determine hardness and investigate the indentation size effect.
- Application and analysis of the Nix-Gao model and its modified versions.
Main Results:
- The Nix-Gao model accurately describes the indentation size effect in the Cantor alloy at higher penetration depths.
- Parameters derived from the Nix-Gao model show good correlation with microstructural observations.
- Deviations from the standard Nix-Gao model at submicrometer depths were observed, indicating the need for model refinement.
- A modified Nix-Gao model provided additional insights into the deformation mechanisms at the nanoscale.
Conclusions:
- The Nix-Gao model is a valuable tool for characterizing the mechanical behavior of HEAs like the Cantor alloy, particularly at larger indentation depths.
- Microstructural features significantly influence the hardness and deformation mechanisms, as reflected in the Nix-Gao model parameters.
- Further investigation and modification of indentation models are necessary to fully understand nanoscale deformation mechanisms in HEAs.
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