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Experimental and Thermodynamic Analysis of Laser Clad Cr3C2/Ni Coatings on a Ti6Al4V Substrate Produced with Different Incident Laser Powers
Y-W. Lei, R-L. Sun, Y. Tang and W. Niu

Laser clad Cr3C2/Ni composite coatings were fabricated on Ti6Al4V substrate at different incident laser power using powder mixture of Ni based alloy and Cr3C2 as clad material. The microstructure of the coatings was investigated by scanning electronic microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The phase fractions, phase compositions and solidification process of the coatings were calculated using Thermo-Calc software. The results show that the microstructure of the coatings strongly depends on the incident laser power. At low incident laser power (3 kW), the coatings were formed of undissolved Cr3C2 particles with many burrs on its surface and cannular Cr23C6 uniformly distributed in g-Ni matrix. At high incident laser power (6 kW), the coatings consisted of TiC dendrites and lamellar CrB distributed in g-Ni matrix. There exhibits an excellent agreement between the experimental data and the theoretical results. It is beneficial to understanding the microstructure evolution in the coatings and to designing coatings with desirable microstructure and mechanical properties.

Keywords: CO2 laser, laser cladding, Cr3C2/Ni, titanium alloy, Ti6Al4V, thermodynamic, coating, microstructure, Thermo-Calc

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