Study the influence of laser energy density on the amorphous content and properties of Fe-based amorphous coatings

To investigate the effect of laser energy density on microstructure and properties, the Fe_41.5Co_12.2Cr_7.4Mo_37.3C_0.3B_0.5Y_0.4Al_0.4 (at. %) amorphous coatings were fabricated by employing different laser energy density (10 J/mm²–60 J/mm²) via laser cladding technique. A detailed study was conducted on the microstructure, geometric morphology, amorphous content and properties of the coatings. It can be found that the Fe-based amorphous coatings mainly consist of amorphous and α-Fe, Fe₄C, Fe₂₁Mo₂C₆, M₂₃(C, B)₆ phases. Meanwhile, as the laser energy density increases, the width and height of the geometric morphology are increased, which is the result of the Marangoni effect and the heat flux generated by laser energy. However, the corrosion resistance and microhardness display a decreasing trend, which can be attributed to the decrease in amorphous content. The cooling rates were decreased with increasing laser energy density, resulting in a negative correlation between laser energy density and amorphous content.