Effect of Scanning Rate on Microstructure and Properties of Fe-Based Amorphous Composite Coatings Prepared by Laser Cladding under Constant Heat Dissipation

Abstract

A water circulation system consisting of a heat dissipation plate was designed to assist laser cladding. The impact of scanning rate under constant cooling conditions on the structure and properties of Fe-based amorphous composite coatings prepared by laser cladding was investigated. The results show that with increasing scanning rate, the coating exhibits different characteristics. At 17 mm/s, the coating has the fastest cooling rate, minimal heat impact, and features predominantly amorphous phase, high hardness, and excellent wear and corrosion resistance. At 11 mm/s and 13 mm/s, local high hardness phases appear, but overall hardness is poor. At 15 mm/s, the coating has the highest hardness (630HV) due to increased amorphous content and solid solution strengthening of supersaturated α-Fe phase. Wear tests reveal low and stable wear rates for samples at 15 mm/s and 17 mm/s, correlating with their uniform hardness. Corrosion resistance tests show the best performance for the 11 mm/s samples, with excellent corrosion resistance. As scanning rate increases, the content of strengthening phases decreases, and the supersaturation of α-Fe phase increases, leading to decreased corrosion resistance. The 17 mm/s samples, with significantly higher amorphous phase content and lower overall content of supersaturated α-Fe phase, exhibit excellent corrosion resistance.