Research on Microstructures and Properties of High-Speed Laser-Cladded Iron-Based Amorphous Alloy Coatings
Fe-Cr-B-Si amorphous alloy powder was successfully prepared on the surface of low-carbon steel with excellent tribological properties by high-speed laser cladding.The effects of laser power on the microstructure,hardness,and wear resistance of the amorphous alloy coating were studied.The results show that the content and distribution of the amorphous phase in the coating are related to the laser power,which affects the dilution and actual cooling rates under a change in heat input.With an increase in laser power,the growth law of microstructure in the coating changes,and the distribution position of amorphous phase switches from the bottom to the top.When the laser power is 2200 W,the microstructure of the coating is mainly composed of an amorphous phase and unformed grain nucleation.The amorphous phase content is approximately 76%and is evenly distributed throughout the coating.The content and distribution of the amorphous phase are the critical factors that affect the hardness and wear resistance of the coating,and the hardness of the amorphous region is approximately 200 HV higher than that of the crystal region.When the amorphous phase is distributed on the top of the coating,the surface hardness and wear resistance of the coating are significantly improved.
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