Effect of forced cooling on the microstructure and properties of Fe-based amorphous composite coatings prepared by laser remelting

A forced cooling system with three cooling plates was designed to assist laser remelting, and the effects of forced cooling on the microstructure and properties of Fe-based amorphous composite coatings prepared by laser remelting were studied. Results show that the content and size of the precipitated crystalline phase decrease, and the crystallites become finer with an increase in the temperature gradient of the forced cooling device. When the temperature of the cooling plate drops to 200 K, the precipitation of the strengthening phase M23(CB)6 is inhibited, and only the alpha-Fe phase precipitates, which has a good toughening effect. The hardness of the coating decreases because the precipitation of the strengthening phase is inhibited. The wear and corrosion resistances of the coatings are significantly improved because of an increase in the content of the amorphous phase and solid solution strengthening of the alpha-Fe phase. However, lowering the temperature of the cooling plate does not result in better performance. At a cooling plate temperature of 200 K, the wear resistance of the coating is the best because the appropriate amount of alpha-Fe phase plays a toughening effect.

Automated summary

Forced cooling system with three cooling plates was used to assist laser remelting of Fe-based amorphous composite coatings. Results showed that an increase in temperature gradient of the cooling device led to a decrease in content and size of precipitated crystalline phase and finer crystallites. Lowering the temperature of the cooling plate improved wear and corrosion resistance of the coatings due to increased amorphous phase content and solid solution strengthening of the alpha-Fe phase. However, excessively low temperature resulted in decreased hardness of the coatings.