Laser surface cladding of Fe-B-C, Fe-B-Si and Fe-BC-Si-Al-C on plain carbon steel

Abstract

In the present study, an attempt has been made to explore deposition of Fe-based amorphous/glassy layer on a plain carbon (AISI 1010) steel by laser surface cladding (LSC) to improve resistance of the substrate to wear and corrosion. Three known glass forming powder blends (under rapid solidification condition) with nominal compositions of 94Fe4B2C, 75Fe15B10Si and 78Fe10BC9Si2Al1C (all in wt.%) were deposited by LSC using a continuous wave Nd:YAG laser under optimum processing conditions determined by preliminary trials. Following LSC, the microstructure and mechanical properties (microhardness and wear resistance) were evaluated in details. Despite the rapid quenching accompanying LSC, none of the coatings developed/retained amorphous/glassy cladding possibly due to large-scale solute redistribution in the clad zone and/or between the clad layer and substrate. The clad microstructure is characterized by fine dispersion of nano/microcrystalline intermetallic and interstitial compounds/phases in ferritic matrix. Both microhardness and wear resistance showed a significant improvement, particularly after LSC with 94Fe4B2C. Potentiodynamic polarization studies in 3.56 wt.% NaCl solution showed that corrosion resistance of the substrate was remarkably improved by LSC with 94Fe4B2C, but slightly deteriorated after LSC with the other two coatings. Thus, it appears that LSC with 94Fe4B2C, among the present coatings, significantly enhances hardness and resistance to wear and corrosion of the substrate, though fails to develop/retain amorphous microstructure under the present laser processing condition.