Mechanical and Structural Characterization of Laser-Cladded Medium-Entropy FeNiCr-B4C Coatings
Artem Okulov1, Yury Korobov1, Alexander Stepchenkov1
1M.N. Mikheev Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, 620108 Ekaterinburg, Russia.
Materials (Basel, Switzerland)
|August 12, 2023
Summary
Adding boron carbide (B4C) to equiatomic medium-entropy alloy (MEA) FeNiCr coatings significantly enhances microhardness. This study demonstrates B4C as a promising strengthening agent for laser-cladded MEA coatings.
Area of Science:
- Materials Science
- Metallurgy
- Surface Engineering
Background:
- Medium-entropy alloys (MEAs) offer tunable properties for advanced applications.
- Laser cladding is a key technique for depositing protective coatings.
- Boron carbide (B4C) is known for its hardness and potential to reinforce metallic matrices.
Purpose of the Study:
- To investigate the effect of B4C additions on the microstructure and mechanical properties of laser-cladded FeNiCr MEA coatings.
- To evaluate the potential of B4C as a strengthening agent in these coatings.
- To characterize the phase structure and bonding of B4C within the FeNiCr matrix.
Main Methods:
- Pulsed laser cladding was used to deposit FeNiCr-B4C coatings (0, 1, 3 wt.% B4C) onto AISI 1040 steel.
- Scanning Electron Microscopy (SEM) analyzed coating microstructure and thickness.
- X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) determined phase composition and structure.
- Raman spectroscopy confirmed the presence of B4C.
- Microhardness and ductility tests evaluated mechanical performance.
Main Results:
- Coatings exhibited uniform thickness (400 ± 20 μm) with a narrow substrate transition zone.
- XRD confirmed a single face-centered cubic (FCC) γ-phase, while TEM revealed a two-phase FCC structure in the 3 wt.% B4C coating.
- Raman spectroscopy confirmed B4C presence via characteristic C-B-C stretching and amorphous carbon peaks.
- Microhardness increased by 16% (1 wt.% B4C) and 38% (3 wt.% B4C).
- Ductility slightly decreased by 4% (1 wt.% B4C) and 10% (3 wt.% B4C).
Conclusions:
- B4C addition is an effective strategy for strengthening laser-cladded FeNiCr MEA coatings.
- The enhanced microhardness comes with a minor reduction in ductility.
- The study highlights the potential of tailored MEA-B4C composites for wear-resistant applications.
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