Improving the consistency of wear properties of the laser clad (FeCoNiCr) 80 Mo 7 W 8 Si 5 coating by different laser remelting strategies

Abstract The overlap zone (OZ) and non-overlap zone (NZ) of multi-track laser cladding give the resulting coatings inconsistent overall properties. Therefore, the effect of various remelting strategies on the non-uniformity of (FeCoNiCr) 80 Mo 7 W 8 Si 5 coatings microstructure and performance was studied. The vertical remelting process decreased the mechanical properties and wear resistance of the resulting coating due to decreased solid solution strengthening resulting from the non-uniform slow diffusion of elements. Marangoni convection due to parallel remelting crossed the OZ and NZ, which increased the coating’s mechanical properties and wear resistance because of solid solution strengthening by Mo and W in α- Fe. This also reduced the performance difference between the OZ and NZ due to the uniform diffusion of μ -phase (Co 7 W 6 , Fe 7 W 6 , Co 7 Mo 6 ) and Mo-Si compounds, the hardness rose to 659.50 HV 0.2 and 687.30 HV 0.2 , corresponding to 508.90 HV 0.2 and 654.50 HV 0.2 , respectively. The discrepancy of the friction coefficient between OZ and NZ decreased from 0.23 to 0.13. The standard deviation of the parallel remelted coating’s hardness decreased to 10.88, which was much lower than that of the un-remelted coating and the vertical remelted coating, which had values of 58.79 and 53.15, respectively. Therefore, parallel-remelted coatings showed better overall stability.